Circuit module and interposer

ABSTRACT

A circuit module includes an interposer, and the interposer includes an element body including a first surface, a first interposer terminal provided on the first surface of the element body, and connected to a first external element, a second interposer terminal provided on the first surface of the element body, and connected to a second external element, a first wiring provided in the element body, and electrically connecting the first interposer terminal and the circuit board with each other, a second wiring provided in the element body, and electrically connecting the second interposer terminal and the circuit board with each other, and a bypass wiring provided in the element body and/or on a surface of the element body, and electrically connecting the first interposer terminal and the second interposer terminal with each other.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2017-013532 filed on Jan. 27, 2017 and is a ContinuationApplication of PCT Application No. PCT/JP2017/042931 filed on Nov. 30,2017. The entire contents of each application are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a circuit module which includes aninterposer used for the connection between a circuit board and anexternal element, and to the interposer.

2. Description of the Related Art

As an invention relating to conventional electronic device, anelectronic device described in Japanese Patent No. 5842850 is known, forexample. The electronic device described in Japanese Patent No. 5842850includes two mounting circuit boards, a flat cable, two male connectors,and two female connectors. The two male connectors are respectivelymounted on the two mounting circuit boards. The two female connectorsare respectively mounted on both ends of the flat cable, which is oneexample of an external element. The two male connectors are connectedwith the two female connectors respectively so that the two mountingcircuit boards are electrically connected with each other through theflat cable.

In the electronic device described in Japanese Patent No. 5842850, themale connector and the female connector have a structure where groundterminals and signal terminals are molded by a resin. Accordingly, themale connector and the female connector are manufactured through a stepof forming the ground terminals and the signal terminals by bending asheet metal, and a step of forming the ground terminals and the signalterminals into an integral body by resin molding. Such a bending stepand a resin molding step require a complicated processing technique. Forthis reason, it is difficult to reduce the size of the male connectorand the female connector.

In view of the above, there is proposed a method for connecting andfixing a cable described in International Application Publication No.WO2014/002757. In the method for connecting and fixing a cable describedin International Application Publication No. WO2014/002757, a guidemember is used in place of the male connectors and the femaleconnectors. To be more specific, the guide member is mounted on aprinted circuit board with solder. Further, a cable is connected to theguide member with solder. The guide member includes linear conductorsand via hole conductors which electrically connect the cable and theprinted circuit board with each other. With such a configuration, thecable and the printed circuit board are electrically connected with eachother through the guide member.

The guide member having the above-described configuration has a stackedstructure. Accordingly, the guide member is manufactured through aprinting step where a conductor layer is printed on an insulator layer,and a lamination step where insulator layers are stacked. Such aprinting step and a lamination step (so-called sheet lamination process)are suitable for manufacturing a large number of small componentscompared with the bending step and the resin molding step. Accordingly,the size of the guide member can be reduced more easily than reducingthe size of the male connector and the female connector.

Recently, there are an increasing number of cases in which three or morecircuit boards are connected with each other through flat cables in anelectronic device, such as in a smartphone. The description will be madewith reference to the example of the case in which a circuit board A, acircuit board B, and a circuit board C are connected with each otherthrough flat cables by the method for connecting and fixing a cabledescribed in International Application Publication No. WO2014/002757,for example. In this case, following three flat cables are necessary.

Flat cable A: connecting the circuit board A and the circuit board Bwith each other

Flat cable B: connecting the circuit board B and the circuit board Cwith each other

Flat cable C: connecting the circuit board C and the circuit board Awith each other

In addition to the above, the following six guide members are necessary.

Guide member A: connecting the flat cable A and the circuit board A witheach other

Guide member B: connecting the flat cable A and the circuit board B witheach other

Guide member C: connecting the flat cable B and the circuit board B witheach other

Guide member D: connecting the flat cable B and the circuit board C witheach other

Guide member E: connecting the flat cable C and the circuit board C witheach other

Guide member F: connecting the flat cable C and the circuit board A witheach other

As described above, the six guide members are necessary to connect thethree circuit boards with each other through the flat cables by themethod for connecting and fixing a cable described in InternationalApplication Publication No. WO2014/002757. Such a configurationincreases an area occupied by the guide members in each circuit board.When the number of circuit boards further increases, the number of guidemembers also further increases, thus further increasing an area occupiedby the guide members in each circuit board.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide interposers andcircuit modules, each of which make it possible to reduce the area of aregion that connects a circuit board and an external element with eachother.

According to a preferred embodiment of the present invention, there isprovided a circuit module including a circuit board including a mainsurface, and an interposer mounted on the main surface of the circuitboard. The interposer includes an element body including a firstsurface, a first interposer terminal and a third interposer terminalprovided on the first surface of the element body and connected to afirst external element, a second interposer terminal and a fourthinterposer terminal provided on the first surface of the element bodyand connected to a second external element, at least one of a firstwiring and a second wiring, and a bypass wiring. The first wiring isprovided in the element body and/or on a surface of the element body,and electrically connects the first interposer terminal and the circuitboard with each other. The second wiring is provided in the element bodyand/or on the surface of the element body, and electrically connects thesecond interposer terminal and the circuit board with each other. Thebypass wiring is provided in the element body and/or on a surface of theelement body, and electrically connects the third interposer terminaland the fourth interposer terminal with each other.

According to a preferred embodiment of the present invention, there isprovided an interposer used in a circuit module including a circuitboard including a main surface, a first external element, and a secondexternal element, the interposer including an element body including afirst surface, a first interposer terminal provided on the first surfaceand connected to the first external element, a second interposerterminal provided on the first surface and connected to the secondexternal element, at least one of a first wiring and a second wiring,and a bypass wiring. The first wiring is provided in the element bodyand/or on a surface of the element body, and electrically connects thefirst interposer terminal and the circuit board with each other. Thesecond wiring is provided in the element body and/or on the surface ofthe element body, and electrically connects the second interposerterminal and the circuit board with each other. The bypass wiring isprovided in the element body and/or on a surface of the element body,and electrically connects the first interposer terminal and the secondinterposer terminal with each other.

According to preferred embodiments of the present invention, it ispossible to reduce the area of a region that connects the circuit boardand the external element with each other.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electronic device 10 according to apreferred embodiment of the present invention.

FIG. 2 is an exploded perspective view of a flat cable 14 a according toa preferred embodiment of the present invention.

FIG. 3 is a perspective view showing flat cables 14 a, 14 b and aninterposer 16 according to a preferred embodiment of the presentinvention.

FIG. 4 is a cross-sectional view taken along a line A-A in FIG. 3.

FIG. 5 is a cross-sectional view taken along a line B-B in FIG. 3.

FIG. 6 is a perspective view of an electronic device 510 according to aComparative Example.

FIG. 7 is a cross-sectional view of an area in the vicinity ofinterposers 616 a, 616 b of electronic device 610 according to theComparative Example.

FIG. 8 is a cross-sectional view of an electronic device 10 a whichincludes an interposer 16 a according to a preferred embodiment of thepresent invention.

FIG. 9 is a cross-sectional view of an electronic device 10 b whichincludes an interposer 16 b according to a preferred embodiment of thepresent invention.

FIG. 10 is a cross-sectional view taken at the same position as thecross-sectional view in FIG. 5.

FIG. 11 is a view of an electronic device 10 c according to a preferredembodiment of the present invention as viewed from above.

FIG. 12 is a cross-sectional view of an electronic device 10 d whichincludes an interposer 16 d according to a preferred embodiment of thepresent invention.

FIG. 13 is a perspective view of an electronic device 10 e whichincludes an interposer 16 e according to a preferred embodiment of thepresent invention.

FIG. 14 is a perspective view of the electronic device 10 e whichincludes the interposer 16 e according to a preferred embodiment of thepresent invention.

FIG. 15 is a cross-sectional view taken along a line C-C in FIG. 13.

FIG. 16 is a cross-sectional view taken along a line C-C in FIG. 13.

FIG. 17 is a perspective view of an electronic device 10 f whichincludes an interposer 16 f according to a preferred embodiment of thepresent invention.

FIG. 18 is a perspective view of the electronic device 10 f whichincludes the interposer 16 f.

FIG. 19 is a cross-sectional view taken along a line D-D in FIG. 17.

FIG. 20 is a cross-sectional view taken along a line E-E in FIG. 17.

FIG. 21 is a perspective view of an interposer 16 g according to apreferred embodiment of the present invention.

FIG. 22 is a cross-sectional view of an electronic device 10 g whichincludes the interposer 16 g according to a preferred embodiment of thepresent invention.

FIG. 23 is a perspective view showing an interposer 16 h according to apreferred embodiment of the present invention.

FIG. 24 is a cross-sectional view taken along a line G-G in FIG. 23.

FIG. 25 is a perspective view showing an interposer 16 i according to apreferred embodiment of the present invention.

FIG. 26 is a perspective view showing an interposer 16 j according to apreferred embodiment of the present invention.

FIG. 27 is a perspective view showing an interposer 16 k according to apreferred embodiment of the present invention.

FIG. 28 is a perspective view showing an interposer 16 l according to apreferred embodiment of the present invention.

FIG. 29 is a view of an interposer 16 according to a preferredembodiment of the present invention as viewed from above.

FIG. 30 is a view of guide members 518 a, 518 b according to a preferredembodiment of the present invention as viewed from above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail below with reference to the accompanying drawings.

Hereinafter, a configuration of an electronic device 10 according to apreferred embodiment will be described with reference to drawings. FIG.1 is a perspective view of the electronic device 10. In FIG. 1, aportion of the internal structure of the electronic device 10 is shown,but a casing, a battery, and the like are omitted. FIG. 2 is an explodedperspective view of a flat cable 14 a.

A circuit board 12 a preferably has a rectangular or substantiallyrectangular plate shape. A direction orthogonal or substantiallyorthogonal to the circuit board 12 a is defined as an up-down direction.A direction along which the long sides of the circuit board 12 a extendwhen the circuit board 12 a is viewed from above is defined as aright-left direction. Further, a direction along which the short sidesof the circuit board 12 a extend when the circuit board 12 a is viewedfrom above is defined as a front-rear direction. The up-down direction,the right-left direction, and the front-rear direction merely provideone example. Accordingly, the up-down direction, the right-leftdirection, and the front-rear direction when the electronic device 10 isused may differ from the up-down direction, the right-left direction,and the front-rear direction shown in FIG. 1.

The electronic device 10 is preferably a radio communication device,such as a smartphone, for example. As shown in FIG. 1, the electronicdevice 10 includes a circuit module 11. The electronic device 10 alsopreferably includes a casing, a battery and the like not shown in thedrawing in addition to the circuit module 11. The circuit module 11preferably includes the circuit boards 12 a to 12 c, the flat cables 14a, 14 b, interposers 16, 18 a, 18 b, a plurality of electroniccomponents 20 a, a plurality of electronic components 20 b, and aplurality of electronic components 20 c.

Each of the circuit boards 12 a to 12 c is preferably a printed circuitboard including circuits in and on the surface thereof. The circuitboards 12 a to 12 c preferably have a rectangular or substantiallyrectangular plate shape as viewed from above. Accordingly, each of thecircuit boards 12 a to 12 c includes an upper surface (one example of amain surface) and a lower surface. The circuit boards 12 b, 12 a, 12 care arranged in one row in this order from the left to the right.

The plurality of electronic components 20 a (one example of a firstelectronic component) are mounted on the upper surface of the circuitboard 12 a. The plurality of electronic components 20 b are mounted onthe upper surface of the circuit board 12 b. The plurality of electroniccomponents 20 c are mounted on the upper surface of the circuit board 12c. The plurality of electronic components 20 a to 20 c are preferablyactive components, such as, for example, semiconductor integratedcircuits, and passive components, such as chip components. In FIG. 1,reference numerals are provided only to representative electroniccomponents 20 a to 20 c from among the plurality of electroniccomponents 20 a to 20 c.

As shown in FIG. 1, the flat cables 14 a, 14 b (the flat cable 14 a isone example of a first flat cable and a first external element, and theflat cable 14 b is one example of a second flat cable and a secondexternal element) are preferably high-frequency signal lines havingflexibility. The flat cables 14 a, 14 b preferably have a linear plateshape which extends in the right-left direction. Hereinafter, thestructure of the flat cable 14 a will be described with reference toFIG. 2.

As shown in FIG. 2, the flat cable 14 a preferably includes a dielectricelement body 30, signal lines 34 a to 34 d, ground conductors 36, 38(one example of a first ground conductor), cable terminals 40 a to 40 d,42 (one example of a first cable terminal), and via hole conductors v1to v8.

As shown in FIG. 2, the dielectric element body 30 extends in theright-left direction as viewed from above. As shown in FIG. 2, thedielectric element body 30 is a stack in which dielectric sheets 32 a to32 e are stacked in this order from the top to the bottom. Thedielectric element body 30 has flexibility.

The dielectric sheets 32 a to 32 e extend in the right-left direction asviewed from above, and preferably have a shape the same or substantiallythe same as that of the dielectric element body 30. The dielectricsheets 32 a to 32 e are preferably made of a thermoplastic resin havingflexibility, such as, for example, polyimide or liquid crystal polymer.The dielectric sheets 32 a to 32 e are preferably formed into anintegral body by thermocompression bonding.

As shown in FIG. 2, the signal lines 34 a to 34 d are provided on theupper surface of the dielectric sheet 32 c. The signal lines 34 a to 34d are linear conductor layers which extend in the right-left direction.The signal lines 34 a to 34 d are arranged at equal or substantiallyequal intervals in this order from the rear side to the front side.

As shown in FIG. 2, the ground conductor 36 is preferably provided onthe upper surface of the dielectric sheet 32 b. The ground conductor 36is preferably a solid conductor layer which covers the entire orsubstantially the entire surface of the dielectric sheet 32 b.Accordingly, the ground conductor 36 overlaps with the signal lines 34 ato 34 d as viewed from above. A rectangular opening Op1 is preferablyprovided in the right end of the ground conductor 36. The conductorlayer is not provided to the opening Op1. Therefore, the right ends ofthe signal lines 34 a to 34 d overlap with the opening Op1 so that theright ends of the signal lines 34 a to 34 d do not overlap with theground conductor 36. It may also be configured such that the groundconductor 36 includes a plurality of openings which overlap with thesignal lines 34 a to 34 d, and which are arranged in the right-leftdirection.

As shown in FIG. 2, the ground conductor 38 is provided on the uppersurface of the dielectric sheet 32 d. The ground conductor 38 ispreferably a solid conductor layer which covers an entire orsubstantially the entire surface of the dielectric sheet 32 d.Accordingly, the ground conductor 38 overlaps with the signal lines 34 ato 34 d as viewed from above. A rectangular opening Op2 is preferablydefined in the right end of the ground conductor 38. The conductor layeris not provided to the opening Op2. Therefore, the right ends of thesignal lines 34 a to 34 d overlap with the opening Op2 so that the rightends of the signal lines 34 a to 34 d do not overlap with the groundconductor 38.

As described above, the signal lines 34 a to 34 d are sandwiched betweenthe ground conductors 36, 38 from the upper and lower sides.Accordingly, the signal lines 34 a to 34 d and the ground conductors 36,38 define a strip-line structure.

As shown in FIG. 2, the cable terminals 40 a to 40 d are preferablyprovided on the lower surface of the dielectric sheet 32 e. The cableterminals 40 a to 40 d are preferably rectangular or substantiallyrectangular conductor layers. The cable terminals 40 a to 40 d arearranged in this order from the rear side to the front side. The cableterminals 40 a to 40 d respectively overlap with the right ends of thesignal lines 34 a to 34 d as viewed from above.

As shown in FIG. 2, the cable terminal 42 is provided on the lowersurface of the dielectric sheet 32 e. The cable terminal is preferably aconductor layer having a rectangular or substantially rectangular frameshape. The cable terminal 42 surrounds the cable terminals 40 a to 40 das viewed from above.

The via hole conductors v1 to v4 penetrate the dielectric sheets 32 c to32 e in the up-down direction. The via hole conductor v1 connects theright end of the signal line 34 a with the cable terminal 40 a. The viahole conductor v2 connects the right end of the signal line 34 b withthe cable terminal 40 b. The via hole conductor v3 connects the rightend of the signal line 34 c with the cable terminal 40 c. The via holeconductor v4 connects the right end of the signal line 34 d with thecable terminal 40 d. With such a configuration, the cable terminals 40 ato 40 d define and function as input/output terminals through which ahigh frequency signal is input and output.

The via hole conductors v5 to v8 penetrate the dielectric sheets 32 b to32 e in the up-down direction. The via hole conductors v5 to v8 connectthe ground conductors 36, 38 with the cable terminal 42. With such aconfiguration, the cable terminal 42 defines and functions as a groundterminal connected to the ground potential.

The signal lines 34 a to 34 d, the ground conductors 36, 38, and the viahole conductors v1 to v8 are preferably made of, for example, a metalmaterial which contains Ag, Cu, and Al as a main component, and whichhas small resistivity. Further, the cable terminals 40 a to 40 d, 42 arepreferably formed by applying Ni plating and Sn plating to a base madeof a metal material which contains Ag, Cu, and Al as a main component.Ni plating and Au plating, Ni plating and Cu plating, or Ni plating andAg plating may be applied, instead of applying Ni plating and Snplating.

The structure of the left end of the flat cable 14 a is preferably thesame or substantially the same as the structure of the right end of theflat cable 14 a and thus, the description of the left end of the flatcable 14 a is omitted. The structure of the flat cable 14 b ispreferably the same or substantially the same as the structure of theflat cable 14 a and thus, the description of the flat cable 14 b isomitted.

Next, the configuration of the interposer 16 will be described withreference to drawings. FIG. 3 is a perspective view showing the flatcables 14 a, 14 b and the interposer 16. FIG. 4 is a cross-sectionalview taken along a line A-A in FIG. 2. FIG. 5 is a cross-sectional viewtaken along a line B-B in FIG. 2.

As shown in FIG. 3 to FIG. 5, the interposer 16 preferably includes anelement body 60, interposer terminals 64 a to 64 d, 66, 68 a to 68 d,70, 74 a, 74 b, 76 a to 76 n, and wirings R11 to R14, R21 to R24, RB. Inaddition to the interposer terminals 74 a, 74 b, 76 a to 76 n, otherinterposer terminals are also preferably provided on the lower surfaceof the element body 60. However, reference numerals are omitted from theinterposer terminals other than the interposer terminals 74 a, 74 b, 76a to 76 n.

The element body 60 preferably has a rectangular or substantiallyrectangular parallelepiped shape. Accordingly, the element body 60includes an upper surface (one example of a top surface), a lowersurface and side surfaces. The upper surface and the lower surface areparallel or substantially parallel to each other. The lower surface ofthe element body 60 defines a mounting surface which opposes the uppersurface of the circuit board 12 a in mounting the interposer 16 on thecircuit board 12 a. The side surfaces preferably include a frontsurface, a rear surface, a left surface, and a right surface, andconnect the upper surface and the lower surface with each other. Theelement body 60 is a stack in which ceramic layers 62 a to 62 e arestacked in this order from the top to the bottom. The ceramic layers 62a to 62 e are preferably layers having a rectangular shape as viewedfrom above. The ceramic layers 62 a to 62 e are preferably made of LTCC(low temperature co-fired ceramics), for example. However, a materialused to form the ceramic layers 62 a to 62 e is not limited to LTCC.

As shown in FIG. 3, the interposer terminals 64 a to 64 d (one exampleof a first interposer terminal) are provided on the upper surface of theceramic layer 62 a (the upper surface of the element body 60), and arepositioned in a region on the left half of the upper surface of theceramic layer 62 a. The interposer terminals 64 a to 64 d are preferablyrectangular or substantially rectangular conductor layers. Theinterposer terminals 64 a to 64 d are arranged in this order from therear side to the front side.

As shown in FIG. 3, the interposer terminal 66 (one example of the firstinterposer terminal) is provided on the upper surface of the ceramiclayer 62 a (the upper surface of the element body 60). The interposerterminal 66 is a conductor layer having a rectangular frame shape. Theinterposer terminal 66 surrounds the interposer terminals 64 a to 64 das viewed from above. Accordingly, the interposer terminals 64 a to 64d, 66 preferably have the same or substantially the same structure asthe cable terminals 40 a to 40 d, 42.

As shown in FIG. 3, the interposer terminals 68 a to 68 d (one exampleof a second interposer terminal) are preferably provided on the uppersurface of the ceramic layer 62 a (the upper surface of the element body60), and are positioned in a region on the right half of the uppersurface of the ceramic layer 62 a. The interposer terminals 68 a to 68 dare preferably defined by rectangular or substantially rectangularconductor layers. The interposer terminals 68 a to 68 d are arranged inthis order from the rear side to the front side.

As shown in FIG. 3, the interposer terminal 70 (one example of thesecond interposer terminal) is provided on the upper surface of theceramic layer 62 a (the upper surface of the element body 60). Theinterposer terminal 70 is preferably a conductor layer having arectangular or substantially rectangular frame shape. The interposerterminal 70 surrounds the interposer terminals 68 a to 68 d as viewedfrom above. Accordingly, the interposer terminals 68 a to 68 d, 70 havethe same structure as cable terminals 50 a to 50 d, 52 (one example of asecond cable terminal).

21 square-shaped interposer terminals and six rectangular interposerterminals are preferably provided on the lower surface of the ceramiclayer 62 e (the lower surface of the element body 60). The 21square-shaped interposer terminals are preferably arranged in, forexample, a 3-row by 7-column matrix. The interposer terminals 76 a to 76g are arranged in the right-left direction on the rearmost row of the 21square-shaped interposer terminals. The interposer terminal 76 a to 76 gare arranged in this order from the right side to the left side. Theinterposer terminals 76 h to 76 n are arranged in the right-leftdirection on the frontmost row of the 21 square-shaped interposerterminals. The interposer terminals 76 h to 76 n are arranged in thisorder from the right side to the left side.

Of the six rectangular interposer terminals, the interposer terminal 74a is provided in the vicinity of the right side of the ceramic layer 62e. The interposer terminal 74 a extends in the front-rear directionalong the right side of the ceramic layer 62 e. Of the six rectangularinterposer terminals, the interposer terminal 74 b is provided in thevicinity of the left side of the ceramic layer 62 e. The interposerterminal 74 b extends in the front-rear direction along the left side ofthe ceramic layer 62 e.

The wiring R11 (one example of a first wiring) electrically connects theinterposer terminal 64 a and the interposer terminal 76 g with eachother. As shown in FIG. 4, the wiring R11 is provided in the elementbody 60. The wiring R11 preferably includes via hole conductors v21,v22, and a wiring conductor 78 f. The wiring conductor 78 f is aconductor layer which is provided on the upper surface of the ceramiclayer 62 b. The via hole conductor v21 penetrates the ceramic layer 62 ain the up-down direction. The via hole conductor v21 connects theinterposer terminal 64 a and the wiring conductor 78 f with each other.The via hole conductor v22 penetrates the ceramic layers 62 b to 62 e inthe up-down direction. The via hole conductor v22 connects the wiringconductor 78 f and the interposer terminal 76 g with each other.

The wiring R12 (one example of the first wiring) electrically connectsthe interposer terminal 66 and the interposer terminal 74 b with eachother. As shown in FIG. 4, the wiring R12 is provided in the elementbody 60. The wiring R12 preferably includes via hole conductors v23, v24and a wiring conductor 78 g. The wiring conductor 78 g is a conductorlayer which is provided on the upper surface of the ceramic layer 62 c.The via hole conductor v23 penetrates the ceramic layers 62 a, 62 b inthe up-down direction. The via hole conductor v23 connects theinterposer terminal 66 and the wiring conductor 78 g with each other.The via hole conductor v24 penetrates the ceramic layers 62 c to 62 e inthe up-down direction. The via hole conductor v24 connects the wiringconductor 78 g and the interposer terminal 74 b with each other.

The wiring R13 (one example of the first wiring) electrically connectsthe interposer terminal 66 and the interposer terminal 76 d with eachother. As shown in FIG. 4, the wiring R13 is provided in the elementbody 60. The wiring R13 preferably includes via hole conductors v18 tov20, and wiring conductors 78 d, 78 e. The wiring conductor 78 d is aconductor layer which is provided on the upper surface of the ceramiclayer 62 b. The wiring conductor 78 e is a conductor layer which isprovided on the upper surface of the ceramic layer 62 c. The via holeconductor v18 penetrates the ceramic layer 62 a in the up-downdirection. The via hole conductor v18 connects the interposer terminal66 and the wiring conductor 78 d with each other. The via hole conductorv19 is a conductor which penetrates the ceramic layer 62 b in theup-down direction. The via hole conductor v19 connects the wiringconductor 78 d and the wiring conductor 78 e with each other. The viahole conductor v20 penetrates the ceramic layers 62 c to 62 e in theup-down direction. The via hole conductor v20 connects the wiringconductor 78 e and the interposer terminal 76 d with each other.

The wiring R14 (one example of the first wiring) electrically connectsthe interposer terminal 66 and the interposer terminal 74 b with eachother. As shown in FIG. 5, the wiring R14 is provided in the elementbody 60. The wiring R14 preferably includes via hole conductors v29,v30, and a wiring conductor 78 j. The wiring conductor 78 j is aconductor layer which is provided on the upper surface of the ceramiclayer 62 c. The via hole conductor v29 penetrates the ceramic layers 62a, 62 b in the up-down direction. The via hole conductor v29 connectsthe interposer terminal 66 and the wiring conductor 78 j with eachother. The via hole conductor v30 penetrates the ceramic layers 62 c to62 e in the up-down direction. The via hole conductor v30 connects thewiring conductor 78 j and the interposer terminal 74 b with each other.

The wiring R21 (one example of a second wiring) electrically connectsthe interposer terminal 68 a with the interposer terminals 76 a, 76 b.As shown in FIG. 4, the wiring R21 is provided in the element body 60.The wiring R21 preferably includes via hole conductors v13 to v15, and awiring conductor 78 b. The wiring conductor 78 b is a conductor layerwhich is provided on the upper surface of the ceramic layer 62 c. Thevia hole conductor v13 penetrates the ceramic layers 62 a, 62 b in theup-down direction. The via hole conductor v13 connects the interposerterminal 68 a and the wiring conductor 78 b with each other. The viahole conductors v14, v15 penetrate the ceramic layers 62 c to 62 e inthe up-down direction. The via hole conductor v14 connects the wiringconductor 78 b and the interposer terminal 76 a with each other. The viahole conductor v15 connects the wiring conductor 78 b and the interposerterminal 76 b with each other.

The wiring R22 (one example of the second wiring) electrically connectsthe interposer terminal 70 and the interposer terminal 76 c with eachother. As shown in FIG. 4, the wiring R22 is provided in the elementbody 60. The wiring R22 preferably includes via hole conductors v16, v17and a wiring conductor 78 c. The wiring conductor 78 c is a conductorlayer which is provided on the upper surface of the ceramic layer 62 b.The via hole conductor v16 penetrates the ceramic layer 62 a in theup-down direction. The via hole conductor v16 connects the interposerterminal 70 and the wiring conductor 78 c with each other. The via holeconductor v17 penetrates the ceramic layers 62 b to 62 e in the up-downdirection. The via hole conductor v17 connects the wiring conductor 78 cand the interposer terminal 76 b with each other.

The wiring R23 (one example of the second wiring) electrically connectsthe interposer terminal 70 and the interposer terminal 74 a with eachother. As shown in FIG. 4, the wiring R23 is provided in the elementbody 60. The wiring R23 preferably includes via hole conductors v11,v12, and a wiring conductor 78 a. The wiring conductor 78 a is aconductor layer which is provided on the upper surface of the ceramiclayer 62 c. The via hole conductor v11 penetrates the ceramic layers 62a, 62 b in the up-down direction. The via hole conductor v11 connectsthe interposer terminal 70 and the wiring conductor 78 a with eachother. The via hole conductor v12 penetrates the ceramic layers 62 c to62 e in the up-down direction. The via hole conductor v12 connects thewiring conductor 78 a and the interposer terminal 74 a with each other.

The wiring R24 (one example of the second wiring) electrically connectsthe interposer terminal 70 and the interposer terminal 74 a with eachother. As shown in FIG. 5, the wiring R24 is provided in the elementbody 60. The wiring R24 preferably includes via hole conductors v25,v26, and a wiring conductor 78 h. The wiring conductor 78 h is aconductor layer which is provided on the upper surface of the ceramiclayer 62 c. The via hole conductor v25 penetrates the ceramic layers 62a, 62 b in the up-down direction. The via hole conductor v25 connectsthe interposer terminal 70 and the wiring conductor 78 h with eachother. The via hole conductor v26 penetrates the ceramic layers 62 c to62 e in the up-down direction. The via hole conductor v26 connects thewiring conductor 78 h and the interposer terminal 74 a with each other.

The bypass wiring RB electrically connects the interposer terminal 64 dand the interposer terminal 68 d with each other. As shown in FIG. 5,the bypass wiring RB is provided in the element body 60. The bypasswiring RB in the present preferred embodiment is provided at a positioncloser to the upper surface of the element body 60 than to the lowersurface of the element body 60. The bypass wiring RB preferably includesvia hole conductors v27, v28, and a wiring conductor 78 i. The wiringconductor 78 i is a conductor layer which is provided on the uppersurface of the ceramic layer 62 b. The via hole conductor v27 penetratesthe ceramic layer 62 a in the up-down direction. The via hole conductorv27 connects the interposer terminal 68 d and the wiring conductor 78 iwith each other. The via hole conductor v28 penetrates the ceramic layer62 a in the up-down direction. The via hole conductor v28 connects theinterposer terminal 64 d and the wiring conductor 78 i with each other.

The wiring conductors 78 a to 78 j and the via hole conductors v11 tov30 are preferably made of, for example, a metal material which containsAg, Cu and the like as a main component, and which has smallresistivity. Further, the interposer terminals 64 a to 64 d, 66, 68 a to68 d, 70, 74 a, 74 b, 76 a to 76 n are preferably formed by applying Niplating and Sn plating to a base made of a metal material which containsAg, Cu and the like as a main component. Ni plating and Au plating, Niplating and Cu plating, or Ni plating and Ag plating may be applied,instead of applying Ni plating and Sn plating.

The interposer 16 having the above-described configuration is mounted onthe upper surface of the circuit board 12 a with solder. First, theinternal structure of the circuit board 12 a will be described withreference to FIG. 4 and FIG. 5.

As shown in FIG. 4 and FIG. 5, the circuit board 12 a preferablyincludes a board body 90, circuit board terminals 92 a, 92 b, 94 a to 94n, a ground conductor 96 (one example of a second ground conductor), andvia hole conductors v40 to v47. The board body 90 is preferably amultilayer board, for example. The ground conductor 96 is a conductorlayer which is provided in the board body 90. The ground conductor 96 ismaintained at the ground potential. The circuit board terminals 92 a, 92b, 94 a to 94 n are provided on the upper surface of the circuit board12 a. The circuit board terminals 92 a, 92 b, 94 a to 94 n respectivelycorrespond to the interposer terminals 74 a, 74 b, 76 a to 76 n. The viahole conductors v40 to v47 are provided in the board body 90, andrespectively connect the circuit board terminals 92 a, 94 c, 94 d, 92 b,92 a, 94 j, 94 k, 92 b with the ground conductor 96.

The circuit board 12 a also preferably includes a circuit which isdefined by wiring conductors and via hole conductors not shown in thedrawing. This circuit is connected to the circuit board terminals 94 a,94 b, 94 e to 94 i, 94 m, 94 n.

The interposer terminals 74 a, 74 b, 76 a to 76 n are respectivelyconnected to the circuit board terminals 92 a, 92 b, 94 a to 94 nthrough solder.

The flat cables 14 a, 14 b are connected to the upper surface of theinterposer 16. To be more specific, the interposer terminals 64 a to 64d, 66 are respectively connected to the cable terminals 40 a to 40 d, 42through solder (one example of a conductive bonding member). Further,the interposer terminals 68 a to 68 d, 70 are respectively connected tothe cable terminals 50 a to 50 d, 52 through solder (one example of theconductive bonding member).

The circuit board 12 a, the interposer 16, and the flat cables 14 a, 14b are connected with each other as described above and thus, the wiringsR11 to R14 electrically connect the flat cable 14 a and the circuitboard 12 a with each other. To be more specific, the wiring R11 connectsthe interposer terminal 64 a and the interposer terminal 76 g with eachother. The interposer terminal 64 a is connected to the cable terminal40 a which is electrically connected to the signal line 34 a. Further,the interposer terminal 76 g is connected to the circuit board terminal94 g which is connected to the circuit (not shown in the drawing) of thecircuit board 12 a. Accordingly, the wiring R11 electrically connectsthe signal line 34 a of the flat cable 14 a and the circuit (not shownin the drawing) of the circuit board 12 a with each other.

Further, the wirings R12, R13, R14 electrically connect the flat cable14 a and the circuit board 12 a with each other. To be more specific,the wirings R12, R14 connect the interposer terminal 66 and theinterposer terminal 74 b with each other, and the wiring R13 connectsthe interposer terminal 66 and the interposer terminal 76 d with eachother. The interposer terminal 66 is preferably connected to the cableterminal 42 which is electrically connected to the ground conductors 36,38. Further, the interposer terminals 76 d, 74 b are respectivelyconnected to the circuit board terminals 94 d, 92 b which are connectedto the ground conductor 96. Accordingly, the wirings R12, R13, R14electrically connect the ground conductors 36, 38 of the flat cable 14 awith the ground conductor 96 of the circuit board 12 a.

The interposer 16 may also include wirings which electrically connectthe flat cable 14 a and the circuit board 12 a with each other inaddition to the wirings R11 to R14.

The wiring R21 electrically connects the flat cable 14 b and the circuitboard 12 a with each other. To be more specific, the wiring R21electrically connects signal lines (not shown in the drawing) of theflat cable 14 b and the circuit (not shown in the drawing) of thecircuit board 12 a with each other. The wiring R21 connects theinterposer terminal 68 a with the interposer terminals 76 a, 76 b. Theinterposer terminal 68 a is connected to the cable terminal 50 a whichis electrically connected to the signal lines of the flat cable 14 b.Further, the interposer terminals 76 a, 76 b are connected to thecircuit board terminals 94 a, 94 b which are connected to the circuit ofthe circuit board 12 a. Accordingly, the wiring R21 electricallyconnects the signal lines of the flat cable 14 b and the circuit of thecircuit board 12 a with each other.

The wirings R22, R23, R24 electrically connect the flat cable 14 b andthe circuit board 12 a with each other. To be more specific, the wiringR22 connects the interposer terminal 70 and the interposer terminal 76 cwith each other, and the wirings R23, R24 connect the interposerterminal 70 and the interposer terminal 74 a with each other. Theinterposer terminal 70 is connected to the cable terminal 52 which isconnected to the ground conductors (not shown in the drawing) of theflat cable 14 b. Further, the interposer terminals 76 c, 74 a arerespectively connected to the circuit board terminals 94 c, 92 a whichare connected to the ground conductor 96. Accordingly, the wirings R22,R23, R24 electrically connect the ground conductors of the flat cable 14b and the ground conductor 96 of the circuit board 12 a with each other.

The interposer 16 may also include wirings which electrically connectthe flat cable 14 b and the circuit board 12 a with each other inaddition to the wirings R21 to R24.

The bypass wiring RB electrically connects the flat cable 14 a and theflat cable 14 b with each other. To be more specific, the bypass wiringRB connects the interposer terminal 64 d and the interposer terminal 68d with each other. The interposer terminal 64 d is connected to thecable terminal 40 d which is connected to the signal line 34 d of theflat cable 14 a. Further, the interposer terminal 68 d is connected tothe cable terminal 50 d which is connected to the signal line (not shownin the drawing) of the flat cable 14 b. Accordingly, the bypass wiringRB electrically connects the signal line 34 d of the flat cable 14 a andthe signal lines of the flat cable 14 b with each other.

The interposer 18 a electrically connects the flat cable 14 a and thecircuit board 12 b with each other. The interposer 18 b electricallyconnects the flat cable 14 b and the circuit board 12 c with each other.Accordingly, the circuit board 12 a and the circuit board 12 b areelectrically connected with each other through the flat cable 14 a, theinterposer 18 a, and the wirings R11 to R14 of the interposer 16. Thecircuit board 12 a and the circuit board 12 c are electrically connectedwith each other through the flat cable 14 b, the interposer 18 b, andthe wirings R21 to R24 of the interposer 16. Further, the circuit board12 b and the circuit board 12 c are electrically connected with eachother through the flat cables 14 a, 14 b, the interposers 18 a, 18 b,and the bypass wiring RB of the interposer 16.

According to the interposer 16, the circuit module 11, and theelectronic device 10 having the above-described configuration, asdescribed below, it is possible to reduce the area of a region thatconnects the circuit boards 12 a to 12 c with the flat cables 14 a, 14b. FIG. 6 is a perspective view of electronic device 510 according to aComparative Example.

The electronic device 510 includes a circuit module 511. The circuitmodule 511 preferably includes circuit boards 512 a to 512 c, flatcables 514 a to 514 c, and guide members 518 a to 518 f. The circuitboards 512 a to 512 c preferably have the same or substantially the samestructures as the circuit boards 12 a to 12 c. The guide members 518 ato 518 f preferably have, for example, the same or a similar structureas the guide member described in Japanese Patent No. 5842850. The guidemembers 518 a, 518 c are mounted on the upper surface of the circuitboard 512 a. The guide members 518 b, 518 e are mounted on the uppersurface of the circuit board 512 b. The guide members 518 d, 518 f aremounted on the upper surface of the circuit board 512 c.

The right end of the flat cable 514 a is connected to the guide member518 a. The left end of the flat cable 514 a is connected to the guidemember 518 b. Accordingly, the circuit board 512 a and the circuit board512 b are electrically connected with each other through the flat cable514 a.

The left end of the flat cable 514 b is connected to the guide member518 c. The right end of the flat cable 514 b is connected to the guidemember 518 d. Accordingly, the circuit board 512 a and the circuit board512 c are electrically connected with each other through the flat cable514 b.

The left end of the flat cable 514 c is connected to the guide member518 e. The right end of the flat cable 514 c is connected to the guidemember 518 f. Accordingly, the circuit board 512 b and the circuit board512 c are electrically connected with each other through the flat cable514 c.

As described above, in the circuit module 511 and the electronic device510 according to the Comparative Example, six guide members 518 a to 518f are necessary in order to connect the circuit boards 512 a to 512 cwith each other. Accordingly, it is necessary for the circuit boards 512a to 512 c to have mounting areas of six guide members 518 a to 518 f.

In view of the above, in the circuit module 11 and the electronic device10, the interposer 16 includes the bypass wiring RB which electricallyconnects the flat cable 14 a and the flat cable 14 b with each other.With such a configuration, it is possible to electrically connect thecircuit board 12 b and the circuit board 12 c with each other withoutusing a flat cable in addition to the flat cables 14 a, 14 b. In otherwords, the circuit board 12 b and the circuit board 12 c areelectrically connected with each other through the flat cables 14 a, 14b, the interposers 18 a, 18 b, and the bypass wiring RB of theinterposer 16. Further, the circuit board 12 a and the circuit board 12b are electrically connected with each other through the flat cable 14a, the interposer 18 a, and the wirings R11 to R14 of the interposer 16.The circuit board 12 a and the circuit board 12 c are electricallyconnected with each other through the flat cable 14 b, the interposer 18b, and the wirings R21 to R24 of the interposer 16. As a result, threeinterposers 16, 18 a, 18 b are sufficient for connecting the circuitboards 12 a to 12 c with each other. As a result, it is possible toreduce the area of a region that connects the circuit boards 12 a to 12c with the flat cables 14 a, 14 b.

In the circuit module 511 and the electronic device 510, three flatcables 514 a to 514 c are used to connect the circuit boards 512 a to512 c with each other. On the other hand, in the circuit module 11 andthe electronic device 10, two flat cables 14 a, 14 b are sufficient toconnect the circuit boards 12 a to 12 c with each other. Accordingly, inthe interposer 16 and the electronic device 10, the number of flatcables is able to be reduced.

In the interposer 16, the circuit module 11, and the electronic device10, it is also possible to reduce an insertion loss which may begenerated between the circuit board 12 b and the circuit board 12 c.FIG. 7 is a cross-sectional view of an area in the vicinity ofinterposers 616 a, 616 b of electronic device 610 according to aComparative Example.

In a circuit module 611 and the electronic device 610, a circuit board612 b (not shown in the drawing, and corresponding to the circuit board12 b) and a circuit board 612 c (not shown in the drawing, andcorresponding to the circuit board 12 c) are electrically connected witheach other through a circuit board 612 a, flat cables 614 a, 614 b, andthe interposers 616 a, 616 b. In this example, two interposers 616 a,616 b are separated components. Accordingly, a bypass wiring RB passesthrough the interposer 616 a, the circuit board 612 a, and theinterposer 616 b. Therefore, it is necessary for the bypass wiring RB toextend from the upper surface to the lower surface of each of theinterposers 616 a, 616 b. For this reason, the bypass wiring RB has alarge length and thus, an insertion loss which may be generated betweenthe circuit board 612 b and the circuit board 612 c increases.

On the other hand, in the interposer 16, the circuit module 11, and theelectronic device 10, the bypass wiring RB is provided to the interposer16, but is not provided to the circuit board 12 a. Accordingly, thebypass wiring RB in the interposer 16, the circuit module 11, and theelectronic device 10 is shorter than the bypass wiring RB in the circuitmodule 611 and the electronic device 610. As a result, in the interposer16, the circuit module 11, and the electronic device 10, it is possibleto reduce an insertion loss which may be generated between the circuitboard 12 b and the circuit board 12 c compared with the circuit module611 and the electronic device 610.

Particularly, in the interposer 16, the circuit module 11, and theelectronic device 10, the bypass wiring RB is provided at a positionclose to the upper surface of the element body 60, instead of beingprovided at a position close to the lower surface of the element body 60and thus, the length of the via hole conductors v27, v28 is furtherreduced. As a result, the length of the bypass wiring RB is furtherreduced and thus, it is possible to further reduce an insertion losswhich may be generated between the circuit board 12 b and the circuitboard 12 c.

Hereinafter, an interposer 16 a according to a first modification of apreferred embodiment of the present invention will be described withreference to a drawing. FIG. 8 is a cross-sectional view of electronicdevice 10 a which includes the interposer 16 a. FIG. 8 is across-sectional view taken at the same position as the cross-sectionalview in FIG. 5.

The interposer 16 a preferably differs from the interposer 16 in termsof the structure of a bypass wiring RB. In the interposer 16 a, thebypass wiring RB is provided on the surface of an element body 60. To bemore specific, in the interposer 16 a, the bypass wiring RB includes awiring conductor 78 i, but does not include via hole conductors v27,v28. The wiring conductor 78 i is provided on the surface of a ceramiclayer 62 a. The wiring conductor 78 i connects an interposer terminal 64d and the interposer terminal 68 d with each other. Other structures ofthe interposer 16 a are the same or substantially the same ascorresponding structures of the interposer 16 and thus, the descriptionof other structures is omitted.

According to the interposer 16 a, a circuit module 11 a, and theelectronic device 10 a having the above-described configuration, for thesame reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is possible to reduce the area of a region thatconnects circuit boards 12 a to 12 c with flat cables 14 a, 14 b.Further, according to the interposer 16 a, the circuit module 11 a, andthe electronic device 10 a, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10.

Further, in the interposer 16 a, the circuit module 11 a, and theelectronic device 10 a, it is possible to further reduce an insertionloss which may be generated between the circuit board 12 b and thecircuit board 12 c. To be more specific, the bypass wiring RB of theinterposer 16 a preferably does not include the via hole conductors v27,v28. Accordingly, the bypass wiring RB of the interposer 16 a is shorterthan the bypass wiring RB of the interposer 16 by the lengths of the viahole conductors v27, v28. Therefore, in the interposer 16 a, the circuitmodule 11 a, and the electronic device 10 a, it is possible to furtherreduce an insertion loss which may be generated between the circuitboard 12 b and the circuit board 12 c.

Hereinafter, an interposer 16 b according to a second modification of apreferred embodiment of the present invention will be described withreference to a drawing. FIG. 9 is a cross-sectional view of electronicdevice 10 b which includes the interposer 16 b. FIG. 9 is across-sectional view taken at the same position as the cross-sectionalview in FIG. 5.

The interposer 16 b preferably differs from the interposer 16 in termsof the structure of a bypass wiring RB. In the interposer 16 b, thebypass wiring RB is provided on the surface of and in the element body60. To be more specific, in the interposer 16 b, the bypass wiring RBincludes an interposer terminal 77 and via hole conductors v27, v28. Theinterposer terminal 77 is provided on the lower surface of a ceramiclayer 62 e. The interposer terminal 77 is connected to a circuit boardterminal 97 of a circuit board 12 a through solder. Further, interposerterminals 76 h to 76 n are not provided to the interposer 16 b.

The via hole conductors v27, v28 penetrate ceramic layers 62 a to 62 ein the up-down direction. The via hole conductor v27 connects aninterposer terminal 68 d and the interposer terminal with each other.The via hole conductor v28 connects an interposer terminal 64 d and theinterposer terminal 77 with each other. Other structures of theinterposer 16 b are preferably the same or substantially the same as thecorresponding structures of the interposer 16 and thus, the descriptionof other structures is omitted.

According to the interposer 16 b, a circuit module 11 b, and theelectronic device 10 b having the above-described configuration, for thesame reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is possible to reduce the area of a region thatconnects the circuit boards 12 a to 12 c with the flat cables 14 a, 14b. Further, according to the interposer 16 b, the circuit module 11 b,and the electronic device 10 b, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10. Further, the bypass wiring RB preferablyincludes an intermediate portion at which the interposer terminal andthe circuit board terminal 97 are connected with each other throughsolder, and this intermediate portion has a low resistance value.Accordingly, in the interposer 16 b, the circuit module 11 b, and theelectronic device 10 b, although the bypass wiring RB is routed to thelower surface of the interposer 16 b, it is possible to prevent anincrease in an insertion loss which may be generated between the circuitboard 12 b and the circuit board 12 c.

Hereinafter, an interposer 16 c according to a third modification of apreferred embodiment of the present invention will be described withreference to drawings. FIG. 10 is a cross-sectional view of electronicdevice 10 c which includes the interposer 16 c. FIG. 10 is across-sectional view taken at the same position as the cross-sectionalview in FIG. 5. FIG. 11 is a view of the electronic device 10 c asviewed from above.

The interposer 16 c preferably differs from the interposer 16 in termsof the shape of an element body 60. To be more specific, at least aportion of an upper surface S1 of the element body 60 projects from alower surface S2 of the element body 60. In the present preferredembodiment, the lower surface S2 falls within the range of the uppersurface S1. Hereinafter, a portion of the upper surface S1 whichprojects from the lower surface S2 is referred to as an “eaves portion200”. The eaves portion 200 overlaps with at least a portion of anelectronic component 20 a as viewed from above. Other structures of theinterposer 16 c are the same or substantially the same as thecorresponding structures of the interposer 16 and thus, the descriptionof other structures is omitted.

According to the interposer 16 c, a circuit module 11 c, and theelectronic device 10 c having the above-described configuration, for thesame reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is possible to reduce the area of a region thatconnects circuit boards 12 a to 12 c with flat cables 14 a, 14 b.Further, according to the interposer 16 c, the circuit module 11 c, andthe electronic device 10 c, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10. Further, in the interposer 16 c, thecircuit module 11 c, and the electronic device 10 c, for the same reasonas the interposer 16, the circuit module 11, and the electronic device10, it is possible to further reduce an insertion loss which may begenerated between the circuit board 12 b and the circuit board 12 c.

Further, according to the interposer 16 c, the circuit module 11 c, andthe electronic device 10 c, a larger number of the electronic components20 a is able to be mounted, or the electronic component 20 a having alarger size is able to be mounted. To be more specific, in theinterposer 16 c, at least a portion of the upper surface S1 of theelement body 60 projects from the lower surface S2 of the element body60. With such a configuration, the eaves portions 200 are defined on theelement body 60. The electronic components 20 a are able to be disposedbelow the eaves portions 200. In other words, a region is increased onwhich the electronic components 20 a are able to be mounted. As aresult, according to the interposer 16 c, the circuit module 11 c, andthe electronic device 10 c, a larger number of the electronic components20 a is able to be mounted, or the electronic component 20 a having alarger size is able to be mounted.

In the interposer 16 c, the circuit module 11 c, and the electronicdevice 10 c, the size of an external terminal which is provided on theupper surface of the circuit board 12 a may be increased instead ofincreasing the number of the electronic components 20 a.

The eaves portions 200 may overlap with the entire or substantially theentire electronic components 20 a as viewed from above.

Hereinafter, an interposer 16 d according to a fourth modification of apreferred embodiment of the present invention will be described withreference to a drawing. FIG. 12 is a cross-sectional view of electronicdevice 10 d which includes the interposer 16 d. FIG. 12 is across-sectional view taken at the same position as the cross-sectionalview in FIG. 5.

The interposer 16 d preferably differs from the interposer 16 in termsof the shape of an element body 60. To be more specific, a recessedportion 202 is provided on the lower surface of the element body 60. Therecessed portion 202 is provided such that the center of the lowersurface of the element body 60 is recessed upward. Further, the recessedportion 202 overlaps with at least a portion of an electronic component20 a as viewed from above (one example of the normal direction of theupper surface of a circuit board 12 a). In the present preferredembodiment of the present invention, the recessed portion 202 overlapswith the entire or substantially the entire electronic components 20 aas viewed from above (one example of the normal direction of the uppersurface of the circuit board 12 a). Accordingly, the electroniccomponents 20 a are positioned in the recessed portion 202.

According to the interposer 16 d, a circuit module 11 d, and theelectronic device 10 d having the above-described configuration, for thesame reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is possible to reduce the area of a region thatconnects the circuit boards 12 a to 12 c with flat cables 14 a, 14 b.Further, according to the interposer 16 d, the circuit module 11 d, andthe electronic device 10 d, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10. Further, in the interposer 16 d, thecircuit module 11 d, and the electronic device 10 d, for the same reasonas the interposer 16, the circuit module 11, and the electronic device10, it is possible to further reduce an insertion loss which may begenerated between the circuit board 12 b and the circuit board 12 c.

Further, according to the interposer 16 d, the circuit module 11 d, andthe electronic device 10 d, a larger number of the electronic components20 a is able to be mounted. To be more specific, in the interposer 16 d,the electronic components 20 a are able to also be mounted on a portionof the circuit board 12 a which opposes the recessed portion 202. As aresult, according to the interposer 16 d, the circuit module 11 d, andthe electronic device 10 d, a larger number of the electronic components20 a is able to be mounted.

Hereinafter, an interposer 16 e according to a fifth modification of apreferred embodiment of the present invention will be described withreference to drawings. FIG. 13 and FIG. 14 are perspective views ofelectronic device 10 e which includes the interposer 16 e. FIG. 14 showsa state in which flat cables 14 a, 14 b are removed. FIG. 15 and FIG. 16are cross-sectional views taken along a line C-C in FIG. 13.

The electronic device 10 e includes a circuit module 11 e. As shown inFIG. 13, the circuit module 11 e preferably includes a circuit board 12a, the interposer 16 e, and the flat cables 14 a, 14 b. In the same orsimilar manner as the circuit module 11, the circuit module 11 e alsoincludes circuit boards 12 b, 12 c. However, the circuit boards 12 b, 12c are omitted in FIG. 13.

As shown in FIG. 14 to FIG. 16, the interposer 16 e preferably includesan element body 60, interposer terminals 64 a to 64 d, 68 a to 68 d, 76a to 76 c, a heating terminal 210, heating conductors 212 a, 212 b, viahole conductors v110, v111, and wirings R15, R16. In addition to theinterposer terminals 76 a to 76 c, other interposer terminals are alsoprovided on the lower surface of the element body 60. However, theinterposer terminals other than the interposer terminals 76 a to 76 care omitted.

The element body 60 preferably has a rectangular or substantiallyrectangular parallelepiped shape. The element body 60 is a stack inwhich ceramic layers 62 a to 62 d are stacked in this order from the topto the bottom. The ceramic layers 62 a to 62 d are layers preferablyhaving a rectangular or substantially rectangular shape as viewed fromabove. The ceramic layers 62 a to 62 d are preferably made of LTCC (lowtemperature co-fired ceramics), for example.

As shown in FIG. 14, the interposer terminals 64 a to 64 d arepreferably provided on the upper surface of the ceramic layer 62 a (theupper surface of the element body 60), and are positioned in a region onthe front half of the upper surface of the ceramic layer 62 a. Theinterposer terminals 64 a to 64 d are preferably rectangular orsubstantially rectangular conductor layers. The interposer terminals 64a to 64 d are arranged in a 2-row by 2-column matrix.

As shown in FIG. 14, the interposer terminals 68 a to 68 d are providedon the upper surface of the ceramic layer 62 a (the upper surface of theelement body 60), and are positioned in a region on the rear half of theupper surface of the ceramic layer 62 a. The interposer terminals 68 ato 68 d are preferably rectangular or substantially rectangularconductor layers. The interposer terminals 68 a to 68 d are arranged ina 2-row by 2-column matrix.

As shown in FIG. 15 and FIG. 16, the interposer terminals 76 a to 76 care provided on the lower surface of the ceramic layer 62 d (the lowersurface of the element body 60). The interposer terminals 76 a to 76 care preferably rectangular or substantially rectangular conductorlayers. The interposer terminals 76 a to 76 c are arranged in this orderfrom the right side to the left side.

The wiring R15 (one example of a first wiring) electrically connects theinterposer terminal 64 a and the interposer terminal 76 a with eachother. As shown in FIG. 15 and FIG. 16, the wiring R15 is provided inthe element body 60. The wiring R15 includes a via hole conductor v101.The via hole conductor v101 penetrates the ceramic layers 62 a to 62 din the up-down direction. The via hole conductor v101 connects theinterposer terminal 64 a and the interposer terminal 76 a with eachother.

The wiring R16 (one example of the first wiring) electrically connectsthe interposer terminal 64 b and the interposer terminal 76 b with eachother. As shown in FIG. 15 and FIG. 16, the wiring R16 is provided inthe element body 60. The wiring R16 preferably includes via holeconductors v102, v103 and a wiring conductor 78 k. The wiring conductor78 k is a conductor layer which is provided on the upper surface of theceramic layer 62 c. The via hole conductor v102 penetrates the ceramiclayers 62 a, 62 b in the up-down direction. The via hole conductor v102connects the interposer terminal 64 b and the wiring conductor 78 k witheach other. The via hole conductor v103 penetrates the ceramic layers 62c, 62 d in the up-down direction. The via hole conductor v103 connectsthe wiring conductor 78 k and the interposer terminal 76 b with eachother.

Although not shown in the drawing, the interposer 16 e preferablyincludes wirings R25, R26 and a bypass wiring RB. In the same or similarmanner as the wirings R21 to R24 of the interposer 16, the wirings R25,R26 electrically connect the flat cable 14 b and the circuit board 12 awith each other.

In the same or similar manner as the bypass wiring RB of the interposer16, the bypass wiring RB of the interposer 16 e connects the flat cable14 a and the flat cable 14 b with each other. Accordingly, the bypasswiring RB of the interposer 16 e connects the interposer terminal 64 dand the interposer terminal 68 b with each other. In the same or similarmanner as the bypass wiring RB of the interposer 16, the bypass wiringRB of the interposer 16 e includes via hole conductors and wiringconductors not shown in the drawing.

The heating terminal 210 is provided on the surface other than the lowersurface of the element body 60. In the present preferred embodiment, asshown in FIG. 13 and FIG. 14, the heating terminal 210 is provided onthe upper surface of the ceramic layer 62 a (the upper surface of theelement body 60), and is positioned in a region on the left half of theupper surface of the ceramic layer 62 a. The heating terminal 210 ispreferably a rectangular or substantially rectangular conductor layerwhich extends in the front-rear direction. The heating terminal 210 ispreferably not used for the connection between the flat cables 14 a, 14b and the interposer 16 e.

The heating conductor 212 a is a conductor layer which is provided onthe upper surface of the ceramic layer 62 c. The heating conductor 212 ais provided in the vicinity of the wiring conductor 78 k. The heatingconductor 212 b (one example of a first heating conductor) is aconductor layer which is provided on the upper surface of the ceramiclayer 62 d. In FIG. 15 and FIG. 16, the heating conductor 212 b ispreferably divided into three members. This is to allow the heatingconductor 212 b to avoid the via hole conductors v101, v103.Accordingly, the heating conductor 212 b is one continuous body in crosssection taken at a position different from the position of FIG. 15 andFIG. 16 in the front-rear direction. The heating conductor 212 b isprovided in the vicinity of the via hole conductors v101, v103. Theheating conductor 212 b is provided in the element body 60 at a positioncloser to the lower surface than to the upper surface of the elementbody 60. Further, the heating conductor 212 b opposes the interposerterminals 76 a to 76 c in the up-down direction.

The via hole conductor v110 is a conductor which penetrates the ceramiclayers 62 a, 62 b in the up-down direction. The via hole conductor v110connects the heating terminal 210 and the heating conductor 212 a witheach other. The via hole conductor v111 penetrates the ceramic layer 62c in the up-down direction. The via hole conductor v111 connects theheating conductor 212 a and the heating conductor 212 b with each other.With such a configuration, the heating conductor 212 b is electricallyconnected with the heating terminal 210.

The wiring conductor 78 k, the heating conductors 212 a, 212 b, and thevia hole conductors v101 to v103, v110, v111 are preferably made, forexample, of a metal material which contains Ag, Cu and the like as amain component, and which has small resistivity. Further, the interposerterminals 64 a to 64 d, 68 a to 68 d, 76 a to 76 c are preferably formedby applying Ni plating and Sn plating to a base made of a metal materialwhich contains Ag, Cu and the like as a main component, for example. Niplating and Au plating, Ni plating and Cu plating, or Ni plating and Agplating may be applied, instead of applying Ni plating and Sn plating.

The interposer 16 e having the above-described configuration is mountedon the upper surface of the circuit board 12 a with solder. First, thestructure of the circuit board 12 a will be described with reference toFIG. 15 and FIG. 16.

As shown in FIG. 15 and FIG. 16, the circuit board 12 a preferablyincludes a board body 90, and circuit board terminals 94 a to 94 c. Theboard body 90 is preferably a multilayer board, for example. The circuitboard terminals 94 a to 94 c are provided on the upper surface of thecircuit board 12 a. The circuit board terminals 94 a to 94 crespectively correspond to the interposer terminals 76 a to 76 c. Theinterposer terminals 76 a to 76 c are respectively connected to thecircuit board terminals 94 a to 94 c through solder.

The flat cables 14 a, 14 b are connected to the upper surface of theinterposer 16. To be more specific, the interposer terminals 64 a to 64d are respectively connected to cable terminals 40 a to 40 d (cableterminals 40 c, 40 d being not shown in the drawing) through solder.Further, the interposer terminals 68 a to 68 d are respectivelyconnected to cable terminals (not shown in the drawing) of the flatcable 14 b through solder.

The circuit board 12 a, the interposer 16, and the flat cables 14 a, 14b are connected with each other as described above and thus, the wiringsR15, R16 electrically connect the flat cable 14 a and the circuit board12 a with each other. The wirings R25, R26 (not shown in the drawing)electrically connect the flat cable 14 b and the circuit board 12 a witheach other. Further, the bypass wiring RB (not shown in the drawing)electrically connects the flat cable 14 a and the flat cable 14 b witheach other.

According to the interposer 16 e, the circuit module 11 e, and theelectronic device 10 e having the above-described configuration, for thesame or similar reason as the interposer 16, the circuit module 11, andthe electronic device 10, it is possible to reduce the area of a regionthat connects the circuit boards 12 a to 12 c with the flat cables 14 a,14 b. Further, according to the interposer 16 e, the circuit module 11e, and the electronic device 10 e, the number of flat cables is able tobe reduced for the same or similar reason as the interposer 16, thecircuit module 11, and the electronic device 10. In the interposer 16 e,the circuit module 11 e, and the electronic device 10 e, for the same orsimilar reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is also possible to further reduce an insertionloss which may be generated between the circuit board 12 b and thecircuit board 12 c.

Further, according to the interposer 16 e, the circuit module 11 e, andthe electronic device 10 e, it is possible to separate the interposer 16e from the circuit board 12 a. To be more specific, the interposer 16 eis a small component and thus, it is difficult to mount the interposer16 e on the circuit board 12 a with certainty. For this reason, theremay be a case in which the mounted interposer 16 e is desired to beseparated from the circuit board 12 a so as to correctly mount theinterposer 16 e on the circuit board 12 a again.

In view of the above, the interposer 16 e preferably includes theheating terminal 210, the heating conductors 212 a, 212 b, and the viahole conductors v110, v111. The heating conductor 212 b is electricallyconnected with the heating terminal 210 through the heating conductor212 a and the via hole conductors v110, v111. In other words, theheating conductor 212 b is connected to the heating terminal 210 througha member having higher thermal conductivity than the element body 60.With such a configuration, when the heating terminal 210 is heated by asoldering iron 250 as shown in FIG. 15, heat of the soldering iron 250is transferred to the heating conductors 212 a, 212 b. The heatingconductor 212 a is provided in the vicinity of the wiring conductor 78k, and the heating conductor 212 b is provided in the vicinity of thevia hole conductors v101, v103. Accordingly, heat transferred to theheating conductors 212 a, 212 b is transferred to the wiring conductor78 k and the via hole conductors v101, v103 and, thereafter, istransferred to the interposer terminals 76 a, 76 b. Further, the heatingconductor 212 b is preferably provided in the element body 60 at aposition closer to the lower surface than to the upper surface of theelement body 60. Accordingly, the heating conductor 212 b is positionedin the vicinity of the interposer terminals 76 a to 76 c. Therefore,heat transferred to the heating conductor 212 b is transferred to theinterposer terminals 76 a to 76 c. For this reason, solder fixed to theinterposer terminals 76 a to 76 c is melted. As a result, the interposer16 e is separated from the circuit board 12 a as shown in FIG. 16.

The heating terminal 210 may be heated in mounting the interposer 16 eon the circuit board 12 a.

Hereinafter, an interposer 16 f according to a sixth modification of apreferred embodiment of the present invention will be described withreference to drawings. FIG. 17 and FIG. 18 are perspective views ofelectronic device 10 f which includes the interposer 16 f. FIG. 18 showsa state where flat cables 14 a, 14 b are removed. FIG. 19 is across-sectional view taken along a line D-D in FIG. 17. FIG. 20 is across-sectional view taken along a line E-E in FIG. 17.

The interposer 16 f preferably differs from the interposer 16 e in termsof a fact that the interposer 16 f includes heating terminals 214 a, 214b, heating conductors 216 a, 216 b, and via hole conductors v120, v121in place of the heating terminal 210, the heating conductors 212 a, 212b, and the via hole conductors v110, v111.

The heating terminals 214 a, 214 b (one example of a second heatingterminal) are provided on the surface other than the lower surface of anelement body 60. In the present preferred embodiment, as shown in FIG.17 and FIG. 18, the heating terminals 214 a, 214 b are provided on theupper surface of a ceramic layer 62 a (the upper surface of the elementbody 60), and are positioned in a region on the left half of the uppersurface of the ceramic layer 62 a. The heating terminals 214 a, 214 bare arranged in this order from the front side to the rear side. Theheating terminals 214 a, 214 b are preferably rectangular orsubstantially rectangular conductor layers which extend in thefront-rear direction. The heating terminals 214 a, 214 b are not usedfor the connection between the flat cables 14 a, 14 b and the interposer16 f.

The heating conductor 216 a (one example of a second heating conductor)is a conductor layer which is provided on the upper surface of a ceramiclayer 62 b. In FIG. 19, the heating conductor 216 a is preferablydivided into three members. This is to allow the heating conductor 216 ato avoid via hole conductors v101, v102. Accordingly, the heatingconductor 216 a is one continuous body in cross section taken at aposition different from the position of FIG. 19 in the front-reardirection. The heating conductor 216 a is provided in the vicinity ofthe via hole conductors v101, v102. The heating conductor 216 a isprovided in the element body 60 at a position closer to the uppersurface than to the lower surface of the element body 60. Further, theheating conductor 216 a opposes interposer terminals 64 a, 64 b in theup-down direction.

The via hole conductor v120 penetrates the ceramic layer 62 a in theup-down direction. The via hole conductor v120 connects the heatingterminal 214 a and the heating conductor 216 a with each other. Withsuch a configuration, the heating conductor 216 a is electricallyconnected with the heating terminal 214 a.

The heating conductor 216 b is a conductor layer which is provided onthe upper surface of the ceramic layer 62 b. In FIG. 20, the heatingconductor 216 b is preferably divided into three members. This is toallow the heating conductor 216 b to avoid via hole conductors v104,v105. Accordingly, the heating conductor 216 b is one continuous body incross section taken at a position different from the position of FIG. 20in the front-rear direction. The heating conductor 216 b is provided inthe vicinity of the via hole conductors v104, v105. The heatingconductor 216 b is provided in the element body 60 at a position closerto the upper surface than to the lower surface of the element body 60.Further, the heating conductor 216 b opposes interposer terminals 68 c,68 d in the up-down direction.

The via hole conductor v121 penetrates the ceramic layer 62 a in theup-down direction. The via hole conductor v121 connects the heatingterminal 214 b and the heating conductor 216 b with each other. Withsuch a configuration, the heating conductor 216 b is electricallyconnected with the heating terminal 214 b.

Other structures of the interposer 16 f are preferably the same orsubstantially the same as the corresponding structures of the interposer16 e and thus, the description of other structures is omitted.

According to the interposer 16 f, a circuit module 11 f, and theelectronic device 10 f having the above-described configuration, for thesame reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is possible to reduce the area of a region thatconnects the circuit boards 12 a to 12 c with the flat cables 14 a, 14b. Further, according to the interposer 16 f, the circuit module 11 f,and the electronic device 10 f, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10. In the interposer 16 f, the circuit module11 f, and the electronic device 10 f, for the same or similar reason asthe interposer 16, the circuit module 11, and the electronic device 10,it is also possible to further reduce an insertion loss which may begenerated between the circuit board 12 b and the circuit board 12 c.

Further, according to the interposer 16 f, the circuit module 11 f, andthe electronic device 10 f, it is possible to separate the flat cables14 a, 14 b from the interposer 16 f. To be more specific, the interposer16 f is a small component and thus, it is difficult to connect the flatcables 14 a, 14 b to the interposer 16 f with certainty. For thisreason, there may be a case in which the flat cables 14 a, 14 b aredesired to be separated from the interposer 16 f so as to correctlyconnect the flat cables 14 a, 14 b to the interposer 16 f again.

In view of the above, the interposer 16 f preferably includes theheating terminal 214 a, the heating conductor 216 a, and the via holeconductor v120. The heating conductor 216 a is electrically connectedwith the heating terminal 214 a through the via hole conductor v120. Inother words, the heating conductor 216 a is connected to the heatingterminal 214 a through a member having higher thermal conductivity thanthe element body 60. With such a configuration, when the heatingterminal 214 a is heated by a soldering iron, heat of the soldering ironis transferred to the heating conductor 216 a. The heating conductor 216a is provided in the vicinity of the via hole conductors v101, v102.Accordingly, heat transferred to the heating conductor 216 a istransferred to the via hole conductors v101, v102 and, thereafter, istransferred to the interposer terminals 64 a, 64 b. Further, the heatingconductor 216 a is provided in the element body 60 at a position closerto the upper surface than to the lower surface of the element body 60.Accordingly, the heating conductor 216 a is positioned in the vicinityof the interposer terminals 64 a, 64 b. Therefore, heat transferred tothe heating conductor 216 a is transferred to the interposer terminals64 a, 64 b. For this reason, solder fixed to the interposer terminals 64a, 64 b is melted. As a result, the flat cable 14 a is separated fromthe interposer 16 f.

The interposer 16 f includes the heating terminal 214 b, the heatingconductor 216 b, and the via hole conductor v121. The heating conductor216 b is electrically connected with the heating terminal 214 b throughthe via hole conductor v121. In other words, the heating conductor 216 bis connected to the heating terminal 214 b through a member havinghigher thermal conductivity than the element body 60. With such aconfiguration, when the heating terminal 214 b is heated by a solderingiron, heat of the soldering iron is transferred to the heating conductor216 b. The heating conductor 216 b is provided in the vicinity of thevia hole conductors v104, v105. Accordingly, heat transferred to theheating conductor 216 b is transferred to the via hole conductors v104,v105 and, thereafter, is transferred to the interposer terminals 68 c,68 d. Further, the heating conductor 216 b is provided in the elementbody 60 at a position closer to the upper surface than to the lowersurface of the element body 60. Accordingly, the heating conductor 216 bis positioned in the vicinity of the interposer terminals 68 c, 68 d.Therefore, heat transferred to the heating conductor 216 b istransferred to the interposer terminals 68 c, 68 d. For this reason,solder fixed to the interposer terminals 68 c, 68 d is melted. As aresult, the flat cable 14 b is separated from the interposer 16 f.

The heating terminals 214 a, 214 b may be heated in connecting the flatcables 14 a, 14 b to the interposer 16 f.

The heating terminals 214 a, 214 b may be connected with each other toform one heating terminal.

Hereinafter, an interposer 16 g according to a seventh modification of apreferred embodiment of the present invention will be described withreference to drawings. FIG. 21 is a perspective view of the interposer16 g. FIG. 22 is a cross-sectional view of electronic device 10 g whichincludes the interposer 16 g. A cross-sectional view in FIG. 22 is across-sectional view taken along a line F-F in FIG. 21.

The interposer 16 g preferably differs from the interposer 16 f in termsof a fact that the interposer 16 g further includes a heating terminal210 and a heating conductor 220. The heating terminal 210 (one exampleof a first heating terminal) is provided on the surface other than thelower surface of an element body 60. In the present preferredembodiment, as shown in FIG. 21 and FIG. 22, the heating terminal 210 isprovided on the left surface of the element body 60. The heatingterminal 210 is not used for the connection between flat cables 14 a, 14b and the interposer 16 g.

The heating conductor 220 (one example of a first heating conductor) isa conductor layer which is provided on the upper surface of a ceramiclayer 62 d. In FIG. 22, the heating conductor 220 is preferably dividedinto three members. This is to allow the heating conductor 220 to avoidvia hole conductors v101, v103. Accordingly, the heating conductor 220is one continuous body in cross section taken at a position differentfrom the position of FIG. 22 in the front-rear direction. The heatingconductor 220 is provided in the vicinity of the via hole conductorsv101, v103. The heating conductor 220 is provided in the element body 60at a position closer to the lower surface than to the upper surface ofthe element body 60. Further, the heating conductor 220 opposesinterposer terminals 76 a to 76 c in the up-down direction.

The heating conductor 220 extends to the left surface of the elementbody 60. Accordingly, the heating conductor 220 is connected to theheating terminal 210.

Other structures of the interposer 16 g are preferably the same orsubstantially the same as the corresponding structures of the interposer16 f and thus, the description of other structures is omitted.

According to the interposer 16 g, a circuit module 11 g, and theelectronic device 10 g having the above-described configuration, for thesame or similar reason as the interposer 16, the circuit module 11, andthe electronic device 10, it is possible to reduce the area of a regionthat connects circuit boards 12 a to 12 c with the flat cables 14 a, 14b. Further, according to the interposer 16 g, the circuit module 11 g,and the electronic device 10 g, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10. In the interposer 16 g, the circuit module11 g, and the electronic device 10 g, for the same or similar reason asthe interposer 16, the circuit module 11, and the electronic device 10,it is also possible to further reduce an insertion loss which may begenerated between the circuit board 12 b and the circuit board 12 c.

According to the interposer 16 g, the circuit module 11 g, and theelectronic device 10 g, for the same or similar reason as the interposer16 e, the circuit module 11 e, and the electronic device 10 e, it isalso possible to separate the interposer 16 f from the circuit board 12a.

According to the interposer 16 g, the circuit module 11 g, and theelectronic device 10 g, for the same or similar reason as the interposer16 f, the circuit module 11 f, and the electronic device 10 f, it isalso possible to separate the flat cables 14 a, 14 b from the interposer16 g.

Further, according to the interposer 16 g, the circuit module 11 g, andthe electronic device 10 g, the heating terminals 214 a, 214 b and theheating terminal 210 are provided on different surfaces of the elementbody 60. Accordingly, it is possible to reduce or prevent a heatingterminal to be heated from being erroneously selected.

Hereinafter, an interposer 16 h according to an eighth modification of apreferred embodiment of the present invention will be described withreference to drawings. FIG. 23 is a perspective view showing theinterposer 16 h. FIG. 24 is a cross-sectional view taken along a lineG-G in FIG. 23.

The interposer 16 h preferably differs from the interposer 16 in termsof a fact that the interposer 16 h further includes a metal shield 80.The metal shield 80 covers at least a portion of the side surfaces of anelement body 60. In the interposer 16 h, the metal shield 80 preferablycovers the entire or substantially the entire side surfaces of theelement body 60. Accordingly, the metal shield 80 extends along the sidesurfaces of the element body 60, thus having an annular shape as viewedfrom above.

Further, electronic components 20 a (one example of a second electroniccomponent) are mounted on the upper surface of a circuit board 12 a, andare disposed adjacent to the interposer 16 h. The description“electronic components 20 a are disposed adjacent to the interposer 16h” means that only a space is present between the electronic component20 a and the interposer 16 h, and there is no member, such as anelectronic component, between the electronic component 20 a and theinterposer 16 h. A portion of the metal shield 80 furthest from theupper surface of the circuit board 12 a in the up-down direction isdefined as a “first end portion t1”. A portion of the electroniccomponent 20 a furthest from the upper surface of the circuit board 12 ain the up-down direction is defined as a “second end portion t2”. Adistance h1 from the upper surface of the circuit board 12 a to thefirst end portion t1 is longer than a distance h2 from the upper surfaceof the circuit board 12 a to the second end portion t2. In other words,the metal shield 80 covers the side surfaces of the element body 60 ofthe interposer 16 h to a position higher than the height of theelectronic component 20 a.

In the interposer 16 h, a wiring conductor 78 j extends to the leftsurface of the interposer 16 h. Accordingly, the wiring conductor 78 jis connected to the metal shield 80. As a result, the metal shield 80 iselectrically connected with a ground conductor 96 through the wiringconductor 78 j, a via hole conductor v30, an interposer terminal 74 b, acircuit board terminal 92 b, and a via hole conductor v47. Accordingly,the metal shield 80 is held at the ground potential.

Other structures of the interposer 16 h are preferably the same orsubstantially the same as the corresponding structures of the interposer16 and thus, the description of other structures is omitted.

According to the interposer 16 h, a circuit module 11 h, and electronicdevice 10 h having the above-described configuration, for the same orsimilar reason as the interposer 16, the circuit module 11, and theelectronic device 10, it is possible to reduce the area of a region thatconnects the circuit boards 12 a to 12 c with flat cables 14 a, 14 b.Further, according to the interposer 16 h, the circuit module 11 h, andthe electronic device 10 h, the number of flat cables is able to bereduced for the same reason as the interposer 16, the circuit module 11,and the electronic device 10.

Further, according to the interposer 16 h, the circuit module 11 h, andthe electronic device 10 h, it is possible to reduce or prevent theintrusion of noise from the outside to the inside of the interposer 16h, and it is also possible to reduce or prevent the emission of noisefrom the inside to the outside of the interposer 16 h. To be morespecific, in the interposer 16 h, the metal shield 80 covers at least aportion of the side surfaces of the element body 60. The metal shield 80is held at the ground potential. Accordingly, the metal shield 80absorbs noise which may enter the interposer 16 h from the outside ofthe interposer 16 h. The metal shield 80 also absorbs noise which may beemitted from the inside to the outside of the interposer 16 h. As aresult, according to the interposer 16 h, the circuit module 11 h, andthe electronic device 10 h, it is possible to reduce or prevent theintrusion of noise from the outside to the inside of the interposer 16h, and it is also possible to reduce or prevent the emission of noisefrom the inside to the outside of the interposer 16 h. Therefore, theelectronic component 20 a is able to be disposed in the vicinity of theinterposer 16 h, thus allowing the reduction in size of the circuitmodule 11 h and the electronic device 10 h.

In the interposer 16 h, the metal shield 80 extends along the sidesurfaces of the element body 60 to surround as viewed from above.Accordingly, the metal shield 80 is able to absorb noise which may enterthe interposer 16 h from the front-rear direction or the right-leftdirection of the interposer 16 h. The metal shield 80 is also able toabsorb noise emitted in the front-rear direction or the right-leftdirection of the interposer 16 h. The metal shield 80 is disposed tocover the side surfaces of the element body 60 by enclosing with oneturn and thus, magnetic flux leaking from surfaces other than the sidesurfaces of the element body 60 which oppose components defines a loop.Accordingly, it is possible to reduce or prevent that magnetic fluxinterferes with the components.

The distance h1 from the upper surface of the circuit board 12 a to thefirst end portion t1 is longer than the distance h2 from the uppersurface of the circuit board 12 a to the second end portion t2. In otherwords, the metal shield 80 covers the side surfaces of the element body60 of the interposer 16 h to a position higher than the height of theelectronic component 20 a. With such a configuration, it is possible toreduce or prevent that the interposer 16 h is affected by noise from theelectronic component 20 a, and it is possible to reduce or prevent thatthe electronic component 20 a is affected by noise from the interposer16 h.

Hereinafter, an interposer 16 i according to a ninth modification of apreferred embodiment of the present invention will be described withreference to a drawing. FIG. 25 is a perspective view showing theinterposer 16 i.

The interposer 16 i preferably differs from the interposer 16 h in termsof the structure of a metal shield 80. To be more specific, in theinterposer 16 i, the metal shield 80 covers the lower half of the sidesurfaces of an element body 60. Other structures of the interposer 16 iare preferably the same or substantially the same as the correspondingstructures of the interposer 16 h and thus, the description of otherstructures is omitted.

According to the interposer 16 i having the above-describedconfiguration, for the same or similar reason as the interposer 16 h, itis possible to reduce the area of a region that connects circuit boards12 a to 12 c with flat cables 14 a, 14 b. According to the interposer 16i, the number of flat cables is able to be reduced for the same orsimilar reason as the interposer 16 h. Further, according to theinterposer 16 i, for the same or similar reason as the interposer 16 h,it is possible to reduce or prevent the intrusion of noise from theoutside to the inside of the interposer 16 i, and it is also possible toreduce or prevent the emission of noise from the inside to the outsideof the interposer 16 i. In the interposer 16 i, for the same or similarreason as the interposer 16 h, the metal shield 80 is able to absorbnoise which may enter the interposer 16 i from the front-rear directionor the right-left direction of the interposer 16 i. The metal shield 80is also able to absorb noise emitted in the front-rear direction or theright-left direction of the interposer 16 i. The metal shield 80 coversthe side surfaces of the element body 60 by enclosing with one turn andthus, magnetic flux leaking from surfaces other than the side surfacesof the element body 60 which oppose components defines a loop.Accordingly, it is possible to reduce or prevent that magnetic fluxinterferes with the components.

Further, according to the interposer 16 i, the metal shield 80 covers aportion of the side surface of the element body 60. Accordingly, it ispossible to reduce or prevent that a parasitic capacitance is generatedbetween the metal shield 80 and a circuit in the interposer 16 i.

Hereinafter, an interposer 16 j according to a tenth modification of apreferred embodiment of the present invention will be described withreference to a drawing. FIG. 26 is a perspective view showing theinterposer 16 j.

The interposer 16 j preferably differs from the interposer 16 h in termsof the structure of a metal shield 80. To be more specific, in theinterposer 16 j, the metal shield 80 covers only the front surface of anelement body 60. Other structures of the interposer 16 j are the same orsubstantially the same as the corresponding structures of the interposer16 h and thus, the description of other structures is omitted.

According to the interposer 16 j having the above-describedconfiguration, for the same or similar reason as the interposer 16 h, itis possible to reduce the area of a region that connects circuit boards12 a to 12 c with flat cables 14 a, 14 b. According to the interposer 16j, the number of flat cables is able to be reduced for the same reasonas the interposer 16 h. Further, according to the interposer 16 j, forthe same or similar reason as the interposer 16 h, it is possible toreduce or prevent the intrusion of noise from the outside to the insideof the interposer 16 i, and it is also possible to reduce or prevent theemission of noise from the inside to the outside of the interposer 16 i.

Further, according to the interposer 16 j, the metal shield 80 covers aportion of the side surfaces of the element body 60. Accordingly, it ispossible to reduce or prevent that a parasitic capacitance is generatedbetween the metal shield 80 and a circuit in the interposer 16 j.

Hereinafter, an interposer 16 k according to an eleventh modification ofa preferred embodiment of the present invention will be described withreference to a drawing. FIG. 27 is a perspective view showing theinterposer 16 k.

The interposer 16 k preferably differs from the interposer 16 h in termsof the structure of an element body 60. To be more specific, the elementbody 60 of the interposer 16 h is preferably made of a single material.A material used to make the element body 60 of the interposer 16 h maypreferably be a magnetic material or a non-magnetic material, forexample. On the other hand, the element body 60 of the interposer 16 kis preferably made of a plurality of kinds of materials. The elementbody 60 of the interposer 16 k preferably includes a non-magneticportion 160, a magnetic portion 162, and a non-magnetic portion 164. Thenon-magnetic portion 160, the magnetic portion 162, and the non-magneticportion 164 are stacked so as to be arranged in this order from the topto the bottom. Other structures of the interposer 16 k are preferablythe same or substantially the same as the corresponding structures ofthe interposer 16 h and thus, the description of other structures isomitted.

According to the interposer 16 k having the above-describedconfiguration, for the same or similar reason as the interposer 16 h, itis possible to reduce the area of a region that connects circuit boards12 a to 12 c with flat cables 14 a, 14 b. According to the interposer 16k, the number of flat cables is able to be reduced for the same reasonas the interposer 16 h. Further, according to the interposer 16 k, forthe same or similar reason as the interposer 16 h, it is possible toreduce or prevent the intrusion of noise from the outside to the insideof the interposer 16 k, and it is also possible to reduce or prevent theemission of noise from the inside to the outside of the interposer 16 k.In the interposer 16 k, for the same or similar reason as the interposer16 h, a metal shield 80 is able to absorb noise which may enter theinterposer 16 k from the front-rear direction or the right-leftdirection of the interposer 16 k. The metal shield 80 is also able toabsorb noise emitted in the front-rear direction or the right-leftdirection of the interposer 16 k. The metal shield 80 covers the sidesurfaces of the element body 60 by enclosing with one turn and thus,magnetic flux leaking from surfaces other than the side surfaces of theelement body 60 which oppose components forms a loop. Accordingly, it ispossible to reduce or prevent that magnetic flux interferes with thecomponents.

According to the interposer 16 k, the circuit in the interposer 16 kdefines and functions as a bead inductor.

Further, according to the interposer 16 k, the magnetic portion 162 iscovered by the metal shield 80 so that magnetic flux is enclosed in theelement body 60.

The interposer 16 k may not include the metal shield 80.

Hereinafter, an interposer 16 l according to a twelfth modification of apreferred embodiment of the present invention will be described withreference to a drawing. FIG. 28 is a perspective view showing theinterposer 16 l.

The interposer 16 l preferably differs from the interposer 16 h in termsof the structure of a metal shield 80. To be more specific, in theinterposer 16 l, the metal shield 80 covers the entire or substantiallythe entire side surfaces of an element body 60, and is provided on theupper surface of an element body 60 such that the metal shield 80 has aband shape along the outer edge of the upper surface of the element body60. Other structures of the interposer 16 l are preferably the same orsubstantially the same as the corresponding structures of the interposer16 h and thus, the description of other structures is omitted.

According to the interposer 16 l having the above-describedconfiguration, for the same or similar reason as the interposer 16 h, itis possible to reduce the area of a region that connects circuit boards12 a to 12 c with flat cables 14 a, 14 b. According to the interposer 16l, the number of flat cables is able to be reduced for the same orsimilar reason as the interposer 16 h. Further, according to theinterposer 16 l, for the same or similar reason as the interposer 16 h,it is possible to reduce or prevent the intrusion of noise from theoutside to the inside of the interposer 16 l, and it is also possible toreduce or prevent the emission of noise from the inside to the outsideof the interposer 16 l. In the interposer 16 l, for the same or similarreason as the interposer 16 h, the metal shield 80 is able to absorbnoise which may enter the interposer 16 l from the front-rear directionor the right-left direction of the interposer 16 l. The metal shield 80is also able to absorb noise emitted in the front-rear direction or theright-left direction of the interposer 16 l. The metal shield 80 coversthe side surfaces of the element body 60 by enclosing with one turn andthus, magnetic flux leaking from surfaces other than the side surfacesof the element body 60 which oppose components define a loop.Accordingly, it is possible to reduce or prevent that magnetic fluxinterferes with the components.

The interposer, the circuit module, and the electronic device accordingto the present invention are not limited to the preferred embodiments ofthe interposers 16, 16 a to 161, the circuit modules 11, 11 a to 11 h,and the electronic devices 10, 10 a to 10 h, and various modificationsare conceivable without departing from the gist of the presentinvention.

The respective configurations of the interposers 16, 16 a to 161, thecircuit modules 11, 11 a to 11 h, and the electronic device 10, 10 a to10 h may be combined with each other as desired.

Further, in the circuit modules 11, 11 a to 11 h and the electronicdevice 10, 10 a to 10 h, the interposer terminal and the cable terminalare connected with each other by solder. However, the interposerterminal and the cable terminal may be connected with each other by aconductive bonding member other than solder. The conductive bondingmember other than solder may be a conductive adhesive agent, ananisotropic conductive film or the like. Alternatively, the interposerterminal and the cable terminal may be in direct contact with each otherwithout via the conductive bonding member. In this case, the interposerterminal and the cable terminal are pressure-bonded so that theinterposer terminal and the cable terminal are metallically bonded atthe interface between the interposer terminal and the cable terminal.

Further, in the circuit modules 11, 11 a to 11 h and the electronicdevices 10, 10 a to 10 h, the interposer terminal and the circuit boardterminal are connected with each other by solder. However, theinterposer terminal and the circuit board terminal may be connected witheach other by a conductive bonding member other than solder. Theconductive bonding member other than solder may be a conductive adhesiveagent, for example. Alternatively, the interposer terminal and thecircuit board terminal may be in direct contact with each other withoutvia the conductive bonding member. In this case, the interposer terminaland the circuit board terminal are pressure-bonded so that theinterposer terminal and the circuit board terminal are metallicallybonded at the interface between the interposer terminal and the circuitboard terminal.

The circuit module 11 and the electronic device 10 may include only anyone of the wirings R11 to R13 (first wiring) and the wirings R21 to R23(second wiring). Even in the case in which the circuit module 11 and theelectronic device 10 include only any one of the wirings R11 to R13(first wiring) and the wirings R21 to R23 (second wiring), it ispossible to reduce the area of a region that connects circuit boards 12a to 12 c with the flat cables 14 a, 14 b. Hereinafter, the descriptionwill be provided with reference to an example of the case in whichwirings R11 to R13 are provided, but wirings R21 to R23 are notprovided. FIG. 29 is a view of an interposer 16 as viewed from above.FIG. 30 is a view of guide members 518 a, 518 b as viewed from above.

In the case in which the wirings R21 to R23 are not provided to theinterposer 16, the circuit boards 12 a to 12 c have the followingconnection relationship. The circuit board 12 a and the circuit board 12b are electrically connected with each other by the flat cable 14 a.Further, the circuit board 12 b and the circuit board 12 c areelectrically connected with each other by the flat cables 14 a, 14 b andthe interposer 16. However, the circuit board 12 a and the circuit board12 c are not electrically connected with each other. In this case, threeinterposers 16, 18 a, 18 b are used.

When the above-described connection relationship is realized in thecircuit module 511 and the electronic device 510 according to theComparative Example of the present invention shown in FIG. 6, the flatcable 514 b and the guide members 518 c, 518 d are unnecessary.Accordingly, the circuit board 512 a and the circuit board 512 b areelectrically connected with each other through the flat cable 514 a.Further, the circuit board 512 b and the circuit board 512 c areelectrically connected with each other through the flat cable 514 c. Inthis case, four guide members 518 a, 518 b, 518 e, 518 f are used.

The size relationship between the mounting areas of the threeinterposers 16, 18 a, 18 b and the mounting areas of the four guidemembers 518 a, 518 b, 518 e, 518 f will now be described. Hereinafter,the mounting areas of the interposers 16, 18 a, 18 b and the areas ofthe interposers 16, 18 a, 18 b are used in a distinguished manner. To bemore specific, the mounting areas of the interposers 16, 18 a, 18 b arethe areas of regions that mount the interposers 16, 18 a, 18 b. Theregions that mount the interposers 16, 18 a, 18 b include theinterposers 16, 18 a, 18 b and regions around the interposers 16, 18 a,18 b. On the other hand, the areas of the interposers 16, 18 a, 18 b arethe areas of the interposers 16, 18 a, 18 b as viewed from above in aplan view. The same definition as the mounting areas of the interposers16, 18 a, 18 b and the areas of the interposers 16, 18 a, 18 b is alsoapplied to the mounting areas of the guide members 518 a, 518 b, 518 e,518 f and the areas of the guide members 518 a, 518 b, 518 e, 518 f.

One flat cable 14 a is connected to the interposer 18 a, and one flatcable 14 b is connected to the interposer 18 b. Accordingly, theinterposer 18 a, 18 b is required to have an area which allows one flatcable 14 a, 14 b to be connected to the interposer 18 a, 18 b. On theother hand, one flat cable 514 c is connected to each of the guidemembers 518 e, 518 f. Accordingly, the guide member 518 e, 518 f isrequired to have an area which allows the one flat cable 514 c to beconnected to the guide member 518 e, 518 f. The sum of the areas of theinterposers 18 a, 18 b and the sum of the areas of the guide members 518e, 518 f are preferably equal or substantially equal to each other. As aresult, the sum of the mounting areas of the interposers 18 a, 18 b andthe sum of the mounting areas of the guide members 518 e, 518 f arepreferably equal or substantially equal to each other. Accordingly, thesize relationship between the mounting areas of the three interposers16, 18 a, 18 b and the mounting areas of the four guide members 518 a,518 b, 518 e, 518 f is determined according to the size relationshipbetween the mounting area of the interposer 16 and the mounting areas ofthe guide members 518 a, 518 b.

Two flat cables 14 a, 14 b are connected to the interposer 16.Accordingly, the interposer 16 is required to have an area which allowsthe two flat cables 14 a, 14 b to be connected to the interposer 16. Onthe other hand, one flat cable 514 a is connected to each of the guidemembers 518 a, 518 b. Accordingly, the guide member 518 a, 518 b isrequired to have an area which allows the one flat cable 514 a to beconnected to the guide member 518 a, 518 b. Therefore, the area of theinterposer 16 and the sum of the areas of the guide members 518 a, 518 bare equal or substantially equal to each other.

The mounting area of the interposer 16 is preferably larger than thearea of the interposer 16. To be more specific, to preventshort-circuiting between the interposer 16 and electronic componentsdisposed around the interposer 16, as shown in FIG. 29, the electroniccomponents cannot be disposed in a region A1 disposed around theinterposer 16. Accordingly, the mounting area of the interposer 16 isthe sum of the area of the interposer 16 and the area of the region A1.

The mounting area of the guide members 518 a, 518 b is preferably largerthan the sum of the areas of the guide members 518 a, 518 b. To be morespecific, to prevent short-circuiting between the guide member 518 a andelectronic components disposed around the guide member 518 a, as shownin FIG. 30, the electronic components cannot be disposed in a region A2disposed around the guide member 518 a. Accordingly, the mounting areaof the guide member 518 a is the sum of the area of the guide member 518a and the area of the region A2. In the same manner, the mounting areaof the guide member 518 b is the sum of the area of the guide member 518b and the area of a region A3.

The area of the interposer 16 is preferably equal or substantially equalto the sum of the areas of the guide members 518 a, 518 b. Further, ascan be seen from FIG. 29 and FIG. 30, the sum of the areas of theregions A2, A3 is preferably larger than the area of the region A1.Accordingly, the mounting area of the interposer 16 is smaller than themounting areas of the guide members 518 a, 518 b. For theabove-described reasons, even in the case in which only any one of thewirings R11 to R13 (first wiring) and the wirings R21 to R23 (secondwiring) is provided, it is possible to reduce the area of a region thatconnects the circuit boards 12 a to 12 c with the flat cables 14 a, 14b.

The interposer 16, 16 a to 161 may include a passive component definedby a wiring conductor and a via hole conductor. The passive componentmay preferably be a capacitor, an inductor, a resistor or the like, forexample. However, the interposer 16, 16 a to 161 does not incorporate anactive component, such as an IC. Further, an active component is notmounted on the interposer 16, 16 a to 16 l.

In the electronic device 10 b, the circuit board terminal 97 may beconnected to the ground conductor 96 through the via hole conductor. Inthis case, the bypass wiring RB is electrically connected to the groundconductor 96.

The circuit module 11 includes the circuit boards 12 a to 12 c, the flatcables 14 a, 14 b, the interposers 16, 18 a, 18 b, the plurality ofelectronic components 20 a, the plurality of electronic components 20 b,and the plurality of electronic components 20 c. However, it issufficient that the circuit module 11 includes at least the circuitboard 12 a and the interposer 16. The same definition as the circuitmodule 11 is applied to the circuit modules 11 a to 11 h.

An external element other than the flat cable may be connected to theinterposer 16, 16 a to 16 l. The external element other than the flatcable may be a large-sized circuit board having flexibility, a hardcircuit board having no flexibility or the like, for example.

While preferred embodiments and modified examples of the presentinvention have been described above, it is to be understood thatvariations and modifications will be apparent to those skilled in theart without departing from the scope and spirit of the presentinvention. The scope of the present invention, therefore, is to bedetermined solely by the following claims.

What is claimed is:
 1. An interposer used in a circuit module includinga circuit board including a main surface, a first external element, anda second external element, the interposer comprising: an element bodyincluding a first surface; a first interposer terminal and a thirdinterposer terminal provided on the first surface and connected to thefirst external element; a second interposer terminal and a fourthinterposer terminal provided on the first surface and connected to thesecond external element; both of a first wiring and a second wiring, thefirst wiring being provided in the element body and/or on a surface ofthe element body, and electrically connecting the first interposerterminal and the circuit board with each other, and the second wiringbeing provided in the element body and/or on the surface of the elementbody, and electrically connecting the second interposer terminal and thecircuit board with each other; and a bypass wiring provided in theelement body and/or on a surface of the element body, and electricallyconnecting the third interposer terminal and the fourth interposerterminal with each other; wherein there is no second bypass wiringprovided in or on the element body and electrically connecting a groundconductor of the first external element and a ground conductor of thesecond external element with each other; the third interposer terminaland the fourth interposer terminal do not electrically connect to thecircuit board by wiring located in the element body; the thirdinterposer terminal is electrically connected to a signal line of thefirst external element and is not electrically connected to a groundterminal of the first external element; the third interposer terminal isnot connected to a ground terminal of the interposer; the element bodyincludes a mounting surface and a top surface defining the firstsurface, the mounting surface and the top surface being opposite to eachother; the mounting surface opposes the main surface of the circuitboard, and is located closer to the main surface than to the top surfacein a direction in which the mounting surface opposes the main surface;the interposer is mounted on the circuit board with solder; and theinterposer further includes: a first heating terminal provided on asurface other than the mounting surface of the element body; and a firstheating conductor provided at the element body at a position closer tothe mounting surface than to the top surface, and electrically connectedwith the first heating terminal.
 2. The interposer according to claim 1,wherein the first external element includes a first ground conductor;the circuit board includes a second ground conductor; and the firstwiring electrically connects the first ground conductor and the secondground conductor with each other.
 3. A circuit module comprising: acircuit board including a main surface; and an interposer mounted on themain surface of the circuit board; wherein the interposer includes: anelement body including a first surface; a first interposer terminal anda third interposer terminal provided on the first surface of the elementbody and connected to a first external element; a second interposerterminal and a fourth interposer terminal provided on the first surfaceof the element body and connected to a second external element; both ofa first wiring and a second wiring, the first wiring being provided inthe element body and/or on a surface of the element body, andelectrically connecting the first interposer terminal and the circuitboard with each other, and the second wiring being provided in theelement body and/or on the surface of the element body, and electricallyconnecting the second interposer terminal and the circuit board witheach other; and a bypass wiring provided in the element body and/or on asurface of the element body, and electrically connecting the thirdinterposer terminal and the fourth interposer terminal with each other;there is no second bypass wiring provided in or on the element body andelectrically connecting a ground conductor of the first external elementand a ground conductor of the second external element with each other;the third interposer terminal and the fourth interposer terminal do notelectrically connect to the circuit board by wiring located in theelement body; the third interposer terminal is electrically connected toa signal line of the first external element and is not electricallyconnected to a ground terminal of the first external element; the thirdinterposer terminal is not connected to a ground terminal of theinterposer; the element body includes a mounting surface and a topsurface defining the first surface, the mounting surface and the topsurface being opposite to each other; the mounting surface opposes themain surface of the circuit board, and is located closer to the mainsurface than to the top surface in a direction in which the mountingsurface opposes the main surface; the interposer is mounted on thecircuit board with solder; and the interposer further includes: a firstheating terminal provided on a surface other than the mounting surfaceof the element body; and a first heating conductor provided at theelement body at a position closer to the mounting surface than to thetop surface, and electrically connected with the first heating terminal.4. The circuit module according to claim 3, wherein the circuit modulefurther includes a first electronic component mounted on the mainsurface of the circuit board; at least a portion of the top surfaceprojects from the mounting surface as viewed in a normal direction ofthe main surface of the circuit board; and the portion of the topsurface which projects from the mounting surface overlaps with at leasta portion of the first electronic component as viewed in the normaldirection of the main surface of the circuit board.
 5. The circuitmodule according to claim 3, wherein the circuit module further includesa first electronic component mounted on the main surface of the circuitboard; a recessed portion is provided on the mounting surface; and therecessed portion overlaps with at least a portion of the firstelectronic component as viewed in a normal direction of the main surfaceof the circuit board.
 6. The circuit module according to claim 3,wherein the first heating terminal is not used to connect the firstexternal element or the second external element with the interposer. 7.The circuit module according to claim 3, wherein the first interposerterminal is provided on the top surface, and is connected to the firstexternal element through solder; and the interposer further includes: asecond heating terminal provided on a surface other than the mountingsurface of the element body; and a second heating conductor provided atthe element body at a position closer to the top surface than to themounting surface, and electrically connected with the second heatingterminal.
 8. The circuit module according to claim 3, wherein the firstexternal element includes a first ground conductor; the circuit boardincludes a second ground conductor; and the first wiring electricallyconnects the first ground conductor and the second ground conductor witheach other.
 9. The circuit module according to claim 3, wherein theelement body includes a plurality of ceramic layers that are stacked.10. The circuit module according to claim 3, wherein the circuit modulefurther includes: a first flat cable which includes a first cableterminal, the first flat cable defining the first external element; anda second flat cable which includes a second cable terminal, the secondflat cable defining the second external element; the first interposerterminal and the third interposer terminal are connected to the firstcable terminal by a conductive adhesive agent; and the second interposerterminal and the fourth interposer terminal are connected to the secondcable terminal by the conductive adhesive agent.
 11. The circuit moduleaccording to claim 10, wherein the first flat cable and the second flatcable are signal lines that are provided in a radio communicationdevice.
 12. The circuit module according to claim 10, wherein adirection along which the first flat cable extends from the first cableterminal to a distal end of the first flat cable is different from adirection along which the second flat cable extends from the secondcable terminal to a distal end of the second flat cable.
 13. The circuitmodule according to claim 3, wherein the element body further includes aside surface, the side surface connecting the mounting surface and thetop surface with each other; the interposer further includes a metalshield which covers at least a portion of the side surface.
 14. Thecircuit module according to claim 13, wherein the circuit module furtherincludes a second electronic component mounted on the main surface ofthe circuit board and disposed adjacent to the interposer; a portion ofthe metal shield farthest from the main surface of the circuit board ina normal direction of the main surface of the circuit board is definedas a first end portion; a portion of the second electronic componentfarthest from the main surface of the circuit board in the normaldirection of the main surface of the circuit board is defined as asecond end portion; and a distance from the main surface of the circuitboard to the first end portion is longer than a distance from the mainsurface of the circuit board to the second end portion.
 15. The circuitmodule according to claim 13, wherein the metal shield extends along theside surface to surround the side surface as viewed in the normaldirection of the main surface of the circuit board.
 16. The circuitmodule according to claim 3, wherein at least a portion of the elementbody is made of a magnetic material.
 17. The circuit module according toclaim 3, wherein at least one of the first wiring and the second wiringincludes two via hole conductors and one wiring conductor; and the twovia hole conductors are connected to different portions of the wiringconductor as viewed in a direction perpendicular to the main surface ofthe circuit board.
 18. The circuit module according to claim 3, furthercomprising: a first flat cable; wherein the first flat cable includes afirst cable terminal electrically connected to the first interposerterminal and the third interposer terminal; and the first flat cabledefines the first external element.
 19. The circuit module according toclaim 18, wherein the circuit module further includes a second circuitboard and a second flat cable defining the second external element. 20.The circuit module according to claim 18, further comprising: a secondflat cable defining the second external element; wherein the first flatcable and the second flat cable protrude in different directions fromthe interposer.
 21. The circuit module according to claim 18, furthercomprising: a second flat cable defining the second external element; asecond circuit board; and a third circuit board; wherein the first flatcable is connected to the second circuit board, and the second flatcable is connected to the third circuit board which is different fromthe second circuit board.
 22. An interposer used in a circuit moduleincluding a circuit board including a main surface, a first externalelement, and a second external element, the interposer comprising: anelement body including a first surface; a first interposer terminal anda third interposer terminal provided on the first surface and connectedto the first external element; a second interposer terminal and a fourthinterposer terminal provided on the first surface and connected to thesecond external element; at least one of a first wiring and a secondwiring, the first wiring being provided in the element body and/or on asurface of the element body, and electrically connecting the firstinterposer terminal and the circuit board with each other, and thesecond wiring being provided in the element body and/or on the surfaceof the element body, and electrically connecting the second interposerterminal and the circuit board with each other; and a bypass wiringprovided in the element body and/or on a surface of the element body,and electrically connecting the third interposer terminal and the fourthinterposer terminal with each other; wherein there is no second bypasswiring provided in or on the element body and electrically connecting aground conductor of the first external element and a ground conductor ofthe second external element with each other; a first ground terminal isdisposed so as to surround the first and third interposer terminals anda second ground terminal is disposed so as to surround the second andfourth interposer terminals; the third interposer terminal iselectrically connected to a signal line of the first external elementand is not electrically connected to a ground terminal of the firstexternal element; the third interposer terminal is not connected to aground terminal of the interposer; the element body includes a mountingsurface and a top surface defining the first surface, the mountingsurface and the top surface being opposite to each other; the mountingsurface opposes the main surface of the circuit board, and is locatedcloser to the main surface than to the top surface in a direction inwhich the mounting surface opposes the main surface; the interposer ismounted on the circuit board with solder; and the interposer furtherincludes: a first heating terminal provided on a surface other than themounting surface of the element body; and a first heating conductorprovided at the element body at a position closer to the mountingsurface than to the top surface, and electrically connected with thefirst heating terminal.
 23. A circuit module comprising: a circuit boardincluding a main surface; and an interposer mounted on the main surfaceof the circuit board; wherein the interposer includes: an element bodyincluding a first surface; a first interposer terminal and a thirdinterposer terminal provided on the first surface of the element bodyand connected to a first external element; a second interposer terminaland a fourth interposer terminal provided on the first surface of theelement body and connected to a second external element; at least one ofa first wiring and a second wiring, the first wiring being provided inthe element body and/or on a surface of the element body, andelectrically connecting the first interposer terminal and the circuitboard with each other, and the second wiring being provided in theelement body and/or on the surface of the element body, and electricallyconnecting the second interposer terminal and the circuit board witheach other; and a bypass wiring provided in the element body and/or on asurface of the element body, and electrically connecting the thirdinterposer terminal and the fourth interposer terminal with each other;there is no second bypass wiring provided in or on the element body andelectrically connecting a ground conductor of the first external elementand a ground conductor of the second external element with each other; afirst ground terminal is disposed so as to surround the first and thirdinterposer terminals and a second ground terminal is disposed so as tosurround the second and fourth interposer terminals; the thirdinterposer terminal is electrically connected to a signal line of thefirst external element and is not electrically connected to a groundterminal of the first external element; the third interposer terminal isnot connected to a ground terminal of the interposer; the element bodyincludes a mounting surface and a top surface defining the firstsurface, the mounting surface and the top surface being opposite to eachother; the mounting surface opposes the main surface of the circuitboard, and is located closer to the main surface than to the top surfacein a direction in which the mounting surface opposes the main surface;the interposer is mounted on the circuit board with solder; and theinterposer further includes: a first heating terminal provided on asurface other than the mounting surface of the element body; and a firstheating conductor provided at the element body at a position closer tothe mounting surface than to the top surface, and electrically connectedwith the first heating terminal.
 24. The circuit module according toclaim 23, further comprising: a first flat cable; wherein the first flatcable includes a first cable terminal electrically connected to thefirst interposer terminal and the third interposer terminal; and thefirst flat cable defines the first external element.
 25. The circuitmodule according to claim 24, further comprising: a second flat cabledefining the second external element; wherein the first flat cable andthe second flat cable protrude in different directions from theinterposer.
 26. The circuit module according to claim 24, furthercomprising: a second flat cable defining the second external element; asecond circuit board; and a third circuit board; wherein the first flatcable is connected to the second circuit board, and the second flatcable is connected to the third circuit board which is different fromthe second circuit board.